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second the construction of the necessary appliances and tools, and the third the means or power of setting the instruments in action. Supposing the first of these obstacles removed we might safely count upon overcoming the others. We have arrived at so excellent a pitch of workmanship and quality in everything relating to the production of iron and steel that boring tools could be produced of almost any size and weight, and having regard to the tremendous mechanical agents at our command, it might be asserted that no difficulty would be insurmountable in getting them down. The piercing of the hard vein of quartzite encountered in the Mont Cenis tnnnel, and which has just been successfully got through, is the best proof of what iron and steel tools backed by effective power can accomplish.

they are usually forgotten or at any rate for- it has many blocks of substantially built given, and a complete triumph in many in-stores. It is said to be by far the most adstances recorded of what is but a very poor vanced and comfortable place of residence be display of engineering skill and practical tween the large cities of St. Louis, Chicago, energy and execution. With the subject of and San Francisco. According to Mr. Whitboring is intimately connected the solution of ney's description no city could well be more the various theories relative to the constitu-pleasantly located or blessed with a more tion of the interior of the earth, into which we genial climate, never experiencing the rougher have not penetrated comparatively an inch. storms met with in the mountains above, and having a mild and uniform temperature in summer. Denver city is destined to be the great central depôt of the different railways now in course of construction. It is divided by a rapid stream which furnishes an uns limited supply of water power, whilst sur rounding it are immense deposits of iron-ore, fireclay, and coal, which are being rapidly developed under the direction of eastern capitalists who do not fail properly to estimate the great value of their possessions.

COLORADO AND ITS MINERAL

WEALTH.

NTERNATIONAL exhibitions have done much to develope and bring into notoriety many hidden and comparatively unknown corners of the earth. They have defined the practical value of many a land, and have placed Viewed in a purely scientific and not con- it in its proper position in the scale of nations. structive light, the chief utility of boring mani- Tested by the unfailing standard of their works Leaving this favoured city let us turn to fests itself most strongly in connection with and their productions, countries have been the mineral productions of Colorado. Taking the great and extensive science of geology, suddenly brought prominently before a them in the order of their intrinsic value we and the practical value of the latter will in world which had previously known but little will first notice gold. This mineral is chiefly crease more and more accordingly as the former respecting them. So, the Paris Universal sought in the counties of Gilpin and Cleat is enabled by new applications and improved Exposition, although following closely on the Creek, although many other sections of the instruments to render it more worthy assist- heels of others, is doing good work in defining territory contain gold-bearing veins. The. ance. It is not sufficient that the result of the the progress that various countries have made gold veins, found wholly in the granite forma operation should indicate merely the different within the last few years. And in these days ation, vary in width from a mere streak to descriptions of soil through which the tool of unceasing thought and restless action, a 40ft. or 50ft. in width, the average, however, passes; it should also enable the geologist to very few years suffice to mark a vast stride in being about 4ft. or 5ft. The surface indicadetermine their fossils, their precise character, progressive advancement. Amongst other tion is a light porous quartz, discoloured by the nature of the stratification, and other places of comparatively recent development, oxidation of base metals in which smalt pardetails of equal importance. By a careful and which have greatly advanced during the ticles of gold are disseminated, sometimes in and accurate series of borings conducted in last few years, stands prominently Colorado. the form of small scales, fine dust, or stringy this manner, geological charts can be con- She has progressed, too, under the most un-pieces, but seldom in the form of nuggets. structed with remarkable fidelity and of in-favourable circumstances, having survived a The precious metal, however, is sometimes calculable value to the engineer, the sailor, war of extermination waged by the Indians found in this form, and in the Paris Exposiand the miner. In borings made for obtaining against the settlers. And withal she flourishes tion are a few dozen pieces weighing from half a supply of water the diameter of the tools and presents a highly creditable appearance an ounce to a pound. These are some of has been considerably increased beyond at the World's Show in Paris. Her minerals the finest specimens ever obtained in Colorado, former dimensions, and that of the wells also form a goodly show, and comprise samples which has rarely given such as these. The in a corresponding ratio. It might be ex-from all parts, which, from their character, are value of veins is usually determined by crushpected that in order to diminish the weight of highly indicative of the wealth of her re-ing a few pieces of the surface ore in a hand. the apparatus it would be advantageous to sources, and frora their number at once bespeak mortar, and washing the powder in a pan employ steel. This latter material is used a vast amount of industry. Mr. J. P. Whitney, The ore is seldom so poor as not to exhibit with great success for the "bit" or boring ex- of Boston, Massachusetts, who is the commis- a streak of gold dust at the bottom of the pan. tremity of the instrument, but there are two sioner from the territory, has prepared a Some surface ores are so rich that with a hand difficulties to be surmounted in the application schedule of these mineral contributions, to mortar and a pan, and a few pails of water, from of it to the rods. At present there is a good which he has added some useful and interest- three to ten dollars per day can be obtained deal of trouble occasioned, and a large amount ing information respecting the region and its by one person. The course of the gold veins of care and skill required to be bestowed upon resources. tracts, or "belts" as they are called, is the welding together of the two different north-east by south-west, cropping out at descriptions of iron composing the rod and the one point at surface and disappearing beneath, handle, and this job would become still more where they may be found in their continua arduous were the rod to be made of steel and tion. welded to an iron handle. The remaining difficulty lies in the greater chance of rupture with a steel rod than an iron one when exposed to the action of torsion. Of all the strains to which ironwork is exposed that of severe torsion is most to be feared, both on account of the uncertainty of its action and the want of reliable experiments respecting the best means of counteracting its influence. Numerous experiments have been made with regard to the effects of torsion upon shafts and axles, and rules and formula deduced for proportioning their strength; but these are inapplicable to the case of boring rods, the length of which is out of all proportion to that of the ordinary examples taken as the base of mathematical calculation. If there is one particular description of strain more than another which would test the soundness and strength of a weld it is a violent wrench, which, similar to all strains of torsion, tends to cause one portion of the weld to rotate round the other considered as a fixed axis. Of all engineering works those of boring and sinking are the most uncertain to estimate; any one of a hundred contingencies, and some are sure to be encountered, sufficing to vitiate the most laborious and careful calculations. At the same time it is of all others the one in which the motto "the end justifies the means" receives general acceptance. Notwithstanding that an immense amount of time and money may be consumed in getting down piles and cylinders, and numerous errors and mistakes, pardonable and unpardonable, may be committed, yet when the work is accomplished,

The territory of Colorado is situated directly upon the line of travel from St. Louis and Chicago to San Francisco. It is only a few hundred miles distant from the navigable waters of the Missouri River, and about a Many alluvial deposits containing gold are thousand from the Pacific Ocean. Its average found in the territory, some of which have extent is 380 miles east and west, and 280 been worked to advantage. One peculiarity miles north and south. The Pacific Railway of the Colorado veins is that they invariably has already reached the line of Colorado 800 prove richer the deeper they are sunk upon. miles west of Chicago, and 1,800 miles dis- The gold, however, is not found to any ex tant from New York, and it has contracted to tent in a free state after leaving the surface construct 225 miles during the present summer, ore, it gradually combines with the sulphurets which will bring it to the foot of the mountain of iron and copper, which take the place of range in Colorado. Passengers are now carried the soft and porous surface ore. The great by rail from New York in four days to within percentage of the precious metal is found in 230 miles of Denver city, the capital of timately associated with the sulphurets of iron, Colorado, to which latter point they are daily copper, silver, lead, antimony, and arsenic. taken by coach. It was so lately as 1858 Many miles of shafts have been sunk and that Colorado first came into notice as a likely tunnels run in Colorado, although as yet no mining region, and this was owing to a dis- great depth has been attained. The deepest covery made by some emigrants of gold near shaft at present is one in the Nevada dis the site of Denver. This discovery ssimu-trict, which has been sunk down to 525ft., lated emigration, and in course of time a and exhibits ore superior to any yet previously regular stream set in to Colorado, where just discovered in the lode upon which it is sunk before rot a white resident was to be seen in This ore is now yielding, in an ordinary stamp the territory, except a colony of Mexicans in and pan mill, a sum three times larger than the extreme southern part. The American that expended in mining and treating it. And war, however, did much to check emigration, yet assay shows that scarcely 25 per cent. of added to which the Indian tribes upon the the gold contained in the ore is really extracted plains combined to drive out, or rather to ex- from it. Within the last year a considerable terminate, the invaders. Fearful massacres of quantity of ore taken from several mines the whites took place, the Indians endeavour- was forwarded to Swansea, that skilled expe ing to regain sole possession of the regions rience and modern appliances might be brought they had so long considered exclusively their to bear upon it. The ore thus treated gave own. But help, and with help a turning yields of between 200 dollars and 300 dollars point, came, and since the American war Colo-to the ton, the same ore not yielding more rado has so prospered that she now boasts a population o 36,000, exclusive of Mexicans and Indians. Denver itself contains about 8,000 souls; its streets are regularly laid out, and

than from ten to fifteen dollars per ton by the stamp and pan mills in Colorado, and yet paying a profit upon that amount. There is certainly an opening here for some specu

it has many blocks of substa
1-stores. It is said to be by far the
rvanced and comfortable place of
ltween the large cities of St. L
of and San Francisco. According t
fney's description no city could e
pleasantly located or blessed with
e genial climate, never experiencing
storms met with in the mountains i
having a mild and uniform tempe
summer. Denver city is destinedy
great central depot of the differat
now in course of construction.
by a rapid stream which furnish
limited supply of water power, wis
rounding it are immense deposits of
fireclay, and coal, which are being
developed under the direction a
capitalists who do not fail properly
the great value of their possession

Leaving this favoured city lat
the mineral productions of Colorado, In
them in the order of their intrinsic
will first notice gold. This men
sought in the counties of Gilpin a
Creek, although many other secti
territory contain gold-bearing van
gold veins, found wholly in the gate
ation, vary in width from a mens
40ft, or 50ft. in width, the average, how
being about 4ft. or 5ft. The sur
tion is a light porous quartz, dise
oxidation of base metals in which
ticles of gold are disseminated, or
the form of small scales, fine dust, ra
pieces, but seldom in the form of
The precious metal, however, is
found in this form, and in the Paris
tion are a few dozen pieces weighing
an ounce to a pound. These
the finest specimens ever obtained in Can
which has rarely given such as the
value of veins is usually determine
ing a few pieces of the surface or a
mortar, and washing the powder in
The ore is seldom so poor as not we
a streak of gold dust at the botto
Some surface ores are so rich that vis
mortar and a pan, and a few paise
three to ten dollars per day can be
by one person. The course of the
tracts, or "belts" as they are
north-east by south-west, croppi
one point at surface and disappearin
where they may be found in their
tion.

JUNE 14, 1867.

THE MECHANICS' MAGAZINE.

lative genius to introduce the necessary plant
and machinery to prevent such a golden
waste.

HOT-AIR APPARATUS.
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Silver is plentiful in Colorado, being found in
all the gold mining districts associated with
the ores containing gold. It is not, how-
ever, present in remunerative quantities under
these conditions; it is when isolated from the
gold deposits that its value is manifest. Im-
mense belts of silver veins, thus separated
from those of the gold ores, exist upon the
western declivities of the Rocky Mountain
range. This has only been known to be the
case within the last two years. The chief
localities of silver are the Argentine and the
Griffith districts, the veins there having been
followed to an altitude previously unknown
in mining experience in Colorado. During the
short time that has elapsed since the discovery
of the silver mining regions, good roads have
been made connecting them with the more
settled sections of the territory. Seventy-six
assays of ores from the silver mines of Summit
County made during the past year, show an
average of 121-64 dollars' worth of silver to the
ton of 2,000lb. of ore. Thirty assays of the
same ore made by another chemist at the mint
at Denver showed 130-28 dollars to the ton
of ore. Fletcher Mountain, in the Ten Mile
district, is now being tunnelled into from its
base to its centre by eastern capitalists, the
object being to intersect a lode at great depth
which exhibits upon the surface indications of region. One third of the plains are estimated
great wealth. This vein, known as the to be underlaid with this material, which
"Compton," shows at surface a crevice over abounds universally, except in the mountains.
a mile long, and of an uniform width of 10ft. The coal is now being used for grates, steam
From shafts sunk upon it it has given some purposes, and reverberatory furnaces, and can
of the richest ore obtained in the district. be bought in Denver for from 6 dollars to 10
dollars per ton. Petroleum, too, will serve well
future generations, as inexhaustible quantities
can be obtained in a fluid state from the plains,
and from the coal found in the parks. Springs
are numerous, from which the oil saturates
the ground for hundreds of feet around. The
only well sunk in Colorado for petroleum
gave a yield of 34 barrels per day, from a depth
of 75 feet. Deposits of dry salt are found in
Colorado, and salt springs are plentiful in
some parts, extensive works being in operation
for boiling and evaporating the brine.
Amongst the sundry deposits in Colorado, we
may, in conclusion, mention alum, fluor-spar,
fireclay, gypsum, lime, manganese, zinc, sul-
phur, and soda, which are all found in con-
siderable quantities. Thus favoured with
natural productions, and blessed with a mild
and healthful climate, we may hope in a few
years to see Colorado assume a leading posi-
tion, for which she appears eminently quali-
fied.

There is no lack of copper in Colorado,
where it is plentifully distributed through all
the gold and silver mining regions. Exten-
sive veins have recently been found about
thirty miles south of Denver, running parallel
with the belts of the gold mines. They are
richer than any previous discoveries; they
contain a grey ore, which yields as high as
60 per cent. of metal. The metal is generally
found in the form of sulphurets in the gold
mines, and the deepest shafts exhibit these
sulphurets in immense and continuous masses.
Copper is sometimes found in a native state,
and, according to recent reports, large masses
of native copper are to be seen in the bottoms
and on the sides of some mountain streams.
Not much attention, however, has as yet been
paid to copper as a source of mineral wealth,
although, from the indications, we may con-
clude that it will be found as profitable and
as inexhaustible as gold and silver. Lead
exhibits itself in many of the gold mines in the
form of galena, but diminishes in quantity as
the depth increases. In Ten Mile district it
is more plentiful than in any other; there it
is sometimes found projecting in large masses
above surface upon the line of vein. Pieces HAT the plan in general use for heating
weighing from 500lb. to 1,000lb. are often rooms by open fireplaces or stoves is a
detached in a partly oxidised condition. Upon relic of the olden times and adhered to, as
Fletcher Mountain it is very rich on the surface, many other obsolete methods are, solely for
cropping out in all directions. The galena that reason, there cannot be the shadow of a
is never found free from silver, yielding from doubt. Notwithstanding that the present age
10oz. to 500oz. to the ton of metal. Assays is essentially an age of economy, we might
made by Professor Hayes on samples of galena,
trom nine different districts, give an average
exceeding 130oz. of silver to the ton. Like
copper, lead has not been much sought, in
fact, it has only been obtained for the pur-
pose of fluxing other metals.

Many alluvial deposits containing found in the territory, some of whi been worked to advantage. One of the Colorado veins is that they prove richer the deeper they are The gold, however, is not found tent in a free state after leaving tes ore, it gradually combines with the of iron and copper, which take t the soft and porous surface ore. percentage of the precious metali i timately associated with the sulphu copper, silver, lead, antimony, d Many miles of shafts have been tunnels run in Colorado, although great depth has been attained f shaft at present is one in the trict, which has been sunk dow and exhibits ore superior to any discovered in the lode upon whi This ore is now yielding, in an ada and pan mill, a sun three times that expended in mining and treat yet assay shows that scarcely the gold contained in the ore is real from it. Within the last year quantity of ore taken from was forwarded to Swansea, that sh rience and modern appliances m to bear upon it. The ore the vields of between 200 dollars and to the ton, the same ore not y than from ten to fifteen dollar p stamp and pan mills in Cala profit upon that ing here is

Iron ore is found in beds along the bases of mountains in irregular masses, in the form of limonite of a brown and red colour. It yields from 50 to 70 per cent. of metal, and contains, in addition, manganese and alumina. Little or nothing has been done to develope this metal, one furnace only having been erected, but that even is not running. This is the more to be wondered at, as the deposits at some points are immense, and coal is found in profusion upon the plains in the same localities as the iron. It is, however, but young days yet, and time will doubtless show better things. The presence of coal argues well for the future manufacturing interests of the

TH

HOT-AIR APPARATUS.

almost say of parsimony, we have done very
little towards a real economisation of our fuel
and its products. More caloric passes away
through the kitchen flue of an ordinary house
in one day than would suffice to warm the
whole of its interior for twice that period of
time. There is certainly some truth in the
common observation always adduc d, when
the subject of abolishing open fireplaces is
alluded to, "It looks cheerful." Undoubtedly
it does so, but very few people nowadays sit
much over the fire as it is termed, and the
real reason why they have so great an affection
for its very appearance is that it fails in reality
to accomplish its purpose, and one is obliged
to look first to see if there is a fire before they
begin to feel its warmth. After entering any
large room or building warmed to a certain
comfortable temperature, one never thinks
about a fire or its appearance simply because
they do not feel the want of it. If, by heating

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our houses in winter to the proper temperaturo we took away the necessity for fireplaces, we should soon cease to care about the mere ap The two methods most in pearance of it. favour for heating buildings are those of hot water and hot air, and it is with the latter of of these that we shall concern ourselves at present. We do not intend to enter upon the question of the relative merits of the two methods, but we maintain that the hot-air apparatus, from the economy of its first cost, its facility of introduction, and the rapid and variable production of heat according to the temperature that may be required, is at least on a par with its rivals, and in many instances greatly to be preferred. Among the objections, which are admittedly valid, it is stated that the hot-air apparatus supplies a dry, burning element of heating, occasioned by the contact with metallic surfaces, and also that injurious ingredients are introduced into the pipes which are not carried away by the exhaust pipe as it ought to be. In addition to these must be included the necessity of watching the apparatus very closely and the constant renewal of the fuel, demanding the services almost of a regular-stoker or fireman.

With the view of obviating these disadvantages a hot-air apparatus has been lately the subject of a patent by MM. Geneste and Hercher, a firm well known for the especial attention they devote to all processes and inventions relative to the question of warming and ventilation. This new apparatus is called a Thermoconservator, or preserver of heat, and has the following peculiar advantageous features:-In the first place, unlike many of its rivals, it can burn any description of fuel, whether coal, coke, or charcoal, and at the same time economises the fuel in two ways. It has a large heating surface, and utilises the products of combustion to a maximum by the employment of a firebox of fireclay, an external envelope lined with sand or any nonconductor of heat, and reservoirs of water which impart hygrometric qualities to the air and regenerate as it were the supply of ozone. In this apparatus, when once charged, the combustion will maintain itself for about twenty hours, and one of the improvements introduced is the substitution of a refractory substance for the sides in lieu of the ordinary metallic envelopes used in other appliances. The distinguishing characteristics of this new invention consist principally in the disposition of the firebox, the introduction of a series of tubes of small diameter affording a large amount of heating surface, and the substitution already alluded to. This tout ensemble produces the following effects:-It causes one

appa

salmon from their waters.

life.

kind of hydrogen would that be which is six times denser than the hydrogen we know of? form? Is it not rather something other than What kind of water, acids, &c., would it hydrogen, if such a gas does exist, that is like hydrogen in everything except that it is six times denser.

single charge of fuel to last a long time; it PREPARING TIN PLATES. extracts the maximum quantity of caloric out of the fuel, and protects the metallic portions Copious use of sulphuric acid in the proTHE manufacture of tin plates involves the of the apparatus from becoming too much heated, and consequently burned out. The cess known as the "Black Pickle." This propreceding cut* fig. 1 represents a vertical section cess is both expensive and dangerous to through the centre, and fig. 2 also a vertical health; besides which, the contributions of section at right angles to the former. At the this poison to many of the mountain streams of This of course is on the supposition that it inferior extremity of the firebox A is placed Wales have long since driven the trout and is an essential property of this quasi-hydrogen the grate g. The firebox A is itself protected To abolish the to be of that density; but it is not an essenby the sides C of fireclay which prevent the manifold evils attending this process of pre- tial property of it; for on being excluded exterior envelope from becoming burnt, and paring plates for tinning, has been the aim of from the iron it became like other hydrogen. obviates the replacement always accompanying Mr. T. F. Parsons, of Maindee, who substitutes How, then, can there be an atmosphere of cast iron when subjected to too violent a heat, the more natural method of cleansing by ordinary hydrogen, but six times denser than The firebox is covered by a plate a (see fig. 2). friction. In the process usually employed for ordinary hydrogen? Why, by no other means upon which is superimposed the conical-shaped preparing iron plates for being coated or plated than that of external pressure. But how are box A1, forming the receptacle for the fuel. with tin or its alloys, the oxide, cinders, and we to get that external pressure? Hydrogen In communication with the plate a are the other impurities adhering to the plates are being the lightest thing we know of, it will tubes B terminating at their other extremity removed by the action of the sulphuric acid naturally arrange itself external to all other in the receptacle D, which is surmounted by only. This method involves a considerable matters in any atmosphere. If we assume the chimney or funnel d. There is a small outlay, and the plates become corroded and other matter to exist which is lighter than door at 7 for the purpose of charging the retain their corrosion in the pores of the iron, hydrogen to press externally upon it-and ratus, and another at m (fig. 2), for lighting in spite of the washing and pressing to which doubtless there is such matter, for example, the fire, cleaning, or any other emergency that they are afterwards subjected. Now although nebulous matter-still that will not help us might arise, but it should never be used for the surface has its showy coating of tin, there much; our atmosphere is surrounded with introducing the fuel. Below the firebox is the lurk beneath it the seeds of weakness and short such matter, which is seen, as the zodiacal ashpit G, the orifice of which is situated at 0; withstanding the wear and tear which it might of our earth it certainly is a part of it, and Hence it is often found incapable of light. Though we do not reckon it as part and opened and shut by a slide worked by a small button r. Crowning the apparatus is reasonably be expected to resist. The more with it we take the density of our hydrogen. an annular reservoir k filled with water and natural method of cleansing is that adopted by But is there not an easier way of accounting pierced with holes in its external envelope to Mr. Parsons, who, by simple friction on the for it than by such an assumption, which even allow of the free circulation of the air. A de- surface, makes the plate clean, smooth, and will not account for it without other assumpscription of the actual modus operandi of this bright, the friction taking place in pure water. tions? First, has it been ascertained that little apparatus will be of more practical use The cleansing is effected by means of a simple ordinary soft iron can be made to absorb six to our readers than a dissertation upon its machine composed of guide or feed rollers, times its natural quantity by being heated in details. Having opened the slide e by means which are used to govern the passage of the an atmosphere of hydrogen compressed six of the screw E, a little fuel is placed upon the plates through a pair of polishing rollers. fold? Secondly, has it been ascertained that grate, in the manner usual in commencing to These latter rollers revolve at high velocities, this meteoric iron, after the hydrogen has been get up steam or heat in any machine, and and produce a perfect cleanness and smoothness expelled, will re-absorb three times its bulk lighted. A draught is at once established by of surface. The machines are said to cost under the same conditions that ordinary soft means of the tubes B upon closing the slide about half as much as one pair of cold rolls iron absorbs only one-half its bulk. Till these by the screw E, and it only remains to put in at present cost, and they can be easily worked are done an assumption is hardly admissible. the full charge through the door 7. The air by two boys. They are so constructed that to be heated is introduced into the apparatus of cold rolls, and thus turn out the plate comthey can either be fitted themselves with a pair through small apertures made in its under surface, and after passing through the tubes plete for tinning; or the polishing rolls only B acquires certain salutary properties by the may be fixed to existing cold rolls, two boys evaporation of the water contained in the re-feed and the other to receive. After passing only being then required, as at present, one to servoirs k and k'. The size of the apparatus represented in the cuts is that of one equal to through the machine the plates are then ready 18in. in diameter and 5ft. in height. Its for coating, and the white tin being applied to a surface already bright, must undoubtedly capability of heating equals that of raising give the best results. No pernicious particles of acid are left on the plate to eat away the heart, or to blemish the surface. It is anticipated that in addition to the saving effected by the disuse of the acid, one annealing and one cold rolling, instead of two, will be sufficient to produce plates more durable and having far more perfect reflecting power than are at present turned out.

through 30 deg. Fah. a sufficient quantity of air to warm a space of 325 cubic yards. The following table shows the different sizes of the apparatus and the other details connected with

it:

Weight of Diameter in Height in feet Number of cube fuel for every inches. and decimals. yards heated. 10 hours in

24827

lbs.

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12

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15

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23

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Assuming these experiments to have been absorb three times its own bulk even under made, and that ordinary soft iron will not pressure, nor will meteoric iron re-absorb the same quantity which was previously driven tion, which we think will not involve so many out of it, we will venture just one assumpdifficulties as the assumption of a dense atmosphere of hydrogen. the meteoric iron was expanded into a state Suppose now that of vapour even till it was of the density o ordinary hydrogen, which is not too much to suppose in the case of a shooting star. Then suppose it to enter an atmosphere of ordinary hydrogen in that state. In passing through such an atmosphere it would be cooled and would condense, and in so condensing would enclose much hydrogen and imprison it, and in gradually shrinking and cooling it would compress the hydrogen, and it might easily be to the extent of that in the Lenarto iron. Moreover, this absorption and condensation might all take place in our own atmosphere. PAPER has lately been read at a meet-It is a very interesting phenomenon, and we Aing of the Royal Society, by Thomas should like to see it investigated by some competent head and hand, whether Mr. Graham's or some other equally competent experimentalists. The inferences that have been drawn and the explanations that have hitherto been given do not appear to us to be satisfac

INTERSTELLAR IRON.

Graham, F.R.S., Master of the Mint, on the amount of hydrogen given off by a sample of the Lenarto meteoric iron when in a state of ignition. He found that it gave off three As the temperature or the degrees of tem- times its volume. Now, ordinary malleable perature through which the air can be raised iron will hardly absorb more than one-half its to afford the results given in the above is volume. From this difference the author 30 deg. Fah., it is clear that, except in frosty infers that the iron must have passed through weather, there would be no necessity for using a very dense atmosphere of hydrogen when in so much fuel. It is, undoubtedly, the trouble a state of ignition. We cannot see the force and inconvenience of having to fix up in a of this inference, much less can we agree with house a special apparatus of this kind that one of our contemporaries, who in writing of

prevents our economising our fuel as we ought it says that we must look for this atmosphere
to do, but if it were once taken up by the far beyond our solar system in fact,
builders of houses its advantages would be that we must look upon it as proved
recognised at once. We are gradually dis- that this iron has come from some of the
covering that builders will avail themselves fixed stars, because it is proved by spectrum
of all improvements in house construction, for analysis that some of them contain hydrogen
allthe new houses are fitted up with self-acting Suppose now that this iron has passed through
boilers and other conveniences, provided they a very dense atmosphere of hydrogen, so much
are really satisfied of their utility and their denser than our hydrogen as the amount
permanent economy.
absorbed by the meteoric iron is greater than
the amount we can cause ordinary soft iron to
absorb; for this seems to be the grounds on
But what

We are indebted for the accompanying engraving to our which the inference is drawn. valuable contemporary Le Genie Industriel.

tory; but the matter has received but little attention as yet.

HE

SOCIETY OF ENGINEERS.

TE president, vice-president, council, and a number of members of the Society of Engineers, having just visited the Paris Exhibition, the opportunity was taken by the president, W.H. Le Feuvre, C.E., F.R.G.S., to deliver an address to M. Eugène, Flachet, president of the French Society of Civil Engineers. The following is a of the Society of Engineers, the pleasing duty translation of the address:-Sir,-As president has fallen to me of presenting to you, as president of the Society of Civil Engineers of France, an address on behalf of the council and members of our society. At the last meeting of our council, held in London, it was suggested that it would be very desirable that advantage should

JUNE 14,15

kind of hydrogen would that be ret times denser than the hydr What kind of water, acids b form? Is it not rather something hydrogen, if such a gas does exits hydrogen in everything except that times denser.

This of course is on the sappoint is an essential property of this q to be of that density; but it is t tial property of it; for on ben; from the iron it became like the How, then, can there be an etwas ordinary hydrogen, but six times be ordinary hydrogen? Why, by me en than that of external we to get that external presse pressure. St being the lightest thing we d naturally arrange itselt external matters in any atmosphere. liwa other matter to exist which hydrogen to press externally me doubtless there is such matter nebulous matter-still that wil much; our atmosphere is such matter, which is seen, as the light. Though we do not rekto of our earth it certainly is spl with it we take the density of But is there not an easier way g for it than by such an assumpta will not account for it without other t tions? First, has it been ser ordinary soft iron can be made war times its natural quantity by b an atmosphere of hydrogen c fold? Secondly, has it been ar this meteoric iron, after the hydrgn expelled, will re-absorb three te under the same conditions that iron absorbs only one-half its k are done an assumption is hardly s Assuming these experiments made, and that ordinary sal ira absorb three times its own bak pressure, nor will meteorie inca new same quantity which was perist out of it, we will venture tion, which we think will not difficulties as the assumpton 1atmosphere of hydrogen. Sp the meteoric iron was expand of vapour even till it was of the ordinary hydrogen, which is not suppose in the case of a shooting s suppose it to enter an atmosphere hydrogen in that state. In pas such an atmosphere it would would condense, and in eo e enclose much hydrogen and imise in gradually shrinking and compress the hydrogen, and it to the extent of that in the L Moreover, this absorption and cos might all take place in our own It is a very interesting phenomena should like to see it invest competent head and hard, where ham's or some other equally c rimentalists. The inferences the | drawn and the explanations that ar ! been given do not appear to s tory; but the matter has rece attention as yet.

THE

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be taken of the opportunity arising from the presence of several of our members in Paris, to mark that sense of esteem and high regard in which many of the members of our profession in your country are justly held by us. It was considered that the most appropriate way in which this wish could be carried out would be by seek ing, in the first place, to make known to you the object of this deputation, and requesting you kindly to convey these sentiments to the Société das Ingénieurs Civils of France, in your capacity as president of that distinguished body. I need hardly say, Mr. President, how cordially this proposal met with my entire concurrence, and, more especially, since we have recently had the honour of seeing your name enrolled as one of the members of our Society. This circumstance has afforded us the most lively gratification, and, it is to be hoped, that it may be regarded only as the commencement of that good feeling and friendship which may prevail between the various institutions of this nation and

our own.

In commemorating the great Exhibition of 1867, which we have now come to visit, we cannot but be sensible of the peaceable career opened up to nations by these undertakings. By a singular coincidence, the first idea of an Exhibition was conceived during one of the most stormy and disastrous eras of modern history, as if it then appeared that in the promotion of the Arts and Sciences, the passions of mankind would be restrained, and peace afforded to the world. Little more than half a century has elapsed since the first Napoleon, as a member of the Institut of France, accompanied by Berthollet, Mongé, and Chaptal, paid a visit of inspection to the factories and workshops of Paris, and the great industrial centres of the Empire, with the view of forming an Exhibition of its manufacturing products. Fifty years after that visit, the illustrious Prince Albert, as president of the Society of Arts of London, conceived the idea of an Exhibition which should comprise a display of the collective industries and manufac. tures of all nations, and this was for the first time carried out in the great Exhibition of 1851, in London. These Exhibitions have since that period been repeated from time to time, until at length they have culminated in the vast design we have now come to your capital to witness.

It has been truly said that our age has been one of Exhibitions, where we begin to recogaise the arts of peace striving to assert their predominance over those wars and jealousies of nations, which have done so much to sadden the history of former times, and distract the peace of the world. It must be a matter, therefore, calculated to afford our profession the deepest satisfaction to reflect that our mission is to aid so materially in those works which have for their object the promotion of that peace and concord in the development of which we see the principal nations of Europe now happily engaged. That peaceful emulation and rivalry under which the attraction and magnitude of each successive Exhibition is sought to be increased, serves only to spread with greater force the enlightened ideas by which they are called into existence. We now see, for the first time, as forming part of an International Exhibition, the external world of Nature brought into alliance with the productions of Art and Science; and I am sure it will not but strike every one as adding a very great additional charm to these undertakings, and one which it would be at all times desirable

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these works we have to notice also, that during nence in this work, that they should be honoured this period some of the most marvellous scientific by those, at all events, who, following in the discoveries have been made. To many of your same direction, know how to estimate the diffidistinguished countrymen the world is indebted culties which must have been encountered before for discoveries which now play a most important the dreams of art become converted into part in its affairs; and, no doubt, there are at stone and iron, and made to become the present moment others engaged in the pro- landmarks of history. It is in this spirit secution of researches calculated to prove of vast of admiration, Mr. President, that we offer benefit to the general interests of society. In this address to you, as representing one whose according you that tribute which the indefatig-life has been devoted to these labours. able and successful labours of your great philo- It is the labour of men whose works will live sophers have so richly deserved, I may be after them, and beget the gratitude of posterity. pardoned perhaps for noticing that we, too, have We, therefore, Mr. President, wish you happiness endeavoured to contribute something towards and success, and that you may live to carry out the general good. But, perhaps, the greatest many of those undertakings which history tells triumph of modern times which we have to us to regard as instalments towards the features record is, that at length electrical communica- of a future age. In closing the remarks I have tion has been established between the Old and the honour of addressing to you, I feel it New World. impossible not to recognise the wonderful inspiration given by the illustrious occupant of the throne of your country to all those undertakings likely in any way to serve the public god, either at home or abroad. Especially to your august Emperor is to be attributed the promulgation of those peaceful sentiments which at length seem to have taken possession of the minds of surrounding and adjacent nations. Let us hope that he may be long spared to complete that mighty mission which is entrusted to him; and that in the end it may be said that not only France, but that the world is at peace.

As one of the exponents of the progress of modern civilisation, reference must be made to the locomotive; and, it may be regarded as one of the results of International Exhibitions that, whereas formerly England supplied France with locomotive engines, France has lately sent a large supply of locomotives to England. Whether this is to be attributed to the numerous strikes which have lately taken place in England, and the consequent disorganisation which has resulted between labour and capital, or to some better and more economical method practised under the French system of manufacture, we cannot yet determine. It is certain, however, that in this respect we do not seem to have kept pace with the times, although we have the credit of having been the originators of that wonderful railway system which now traverses every quarter of the globe. It has sometimes occurred to me, as far as I have been led from personal experience to consider the question, that superior skill and science has been brought to bear upon the management of the ironworks of France and Belgium tnan is to be discovered in our own country, and this would, necessarily, have much to do with the different results. For some years past, I have frequently obtained from the Continent samples of iron that our leading ironmasters at home stated it was impossible to produce.

T

ARTESIAN WELLS IN ALGERIA. WENTY-THREE years ago (says the Athen. aum) the French colonists of Algeria made their first attempts to sink artesian wells in their newly-acquired territory; but after boring in two places in the province of Oran to a depth of 98 and 176 mètres without striking water, the attempts were abandoned. In 1856, operations were resumed by the military corps of engineers, and from that date, with two or three exceptions, every boring has succeeded; and at the end of 1861, seventy-five wells were flowing and deliver. ing 4,200,000 litres of water every hour, or 100,000 cubic mètres a-day. The water is limpid and drinkable, but generally a little brackish. The effect of such a supply on the social life and industry of the country may be imagined. A village and date plantations rise up around every well, and the natives, having something to lose, prefer peace to predacity. Thirty-five of the wells are in the Ouled Rir district, which stretches far to the south. The deepest well is 175 mètres, the shallowest 29 mètres, and the total of all the borings amounts to 6,628 mètres. The entire cost, defrayed by a tax on the natives, was 400,000f. Among the material results, we are informed that 150,000 date trees have been planted in the Ouled Rir district alone, besides fruit-trees of other kinds, and more than 2,000 new gardens have been formed. We may expect that these beneficial operations will be continued, for four boring brigades have been established, all well provided with implements, for the purpose of systematic exploration, and to sink wells in places likely to yield water. Guided by years of experience, their failures are now but few, and year by year their knowledge of the local hydrography, surface and subterranean, becomes more com

But as an indication of the progress which has been made in the manufacturing processes and applied sciences in England, it may be observed that, in 1824, the first locomotive constructed by George Stephenson only travelled at the rate of six miles an hour. In 1829 others were constructed which travelled at the rate of fifteen miles per hour. In 1839 locomotives attained a velocity of thirty-seven miles per hour; and at the present moment we have locomotive engines which have reached a speed of seventy miles an hour. These facts clearly demonstrate the vast improvements which have been effected in the mechanical arts within a period of fifty years, and at the same time indicate the possibility of futher improvements yet being made. The immense benefits conferred on nations by the operations of railways will serve in future times to mark the character of the present era. They afforda wonderful means for abridging labour and facilitating the operations of commerce, and thereby the acquisition of capital; and that rapid intercommunication which could scarcely be attained in any other way than by the loco-plete. motive, has led to an entire transformation of the conditions and character of society. En. trusted with all the elements which could be made to life impart to us a

THE ATLANTIC CABLE. Telegraph Construction and Maintenance

to see associated with them in future. If any higher knowledge of the future, the world, from T Company have lost no time in arranging for

hibitions have upon the opinions of mankind, it may readily be seen in that fascination by which so many illustrious personages have been drawn towards your capital, and, by the multitude of visitors arriving from all quarters of the world solely to comtemplate man's handiwork and genius. Princes have bowed down in homage to those principles which constitute the true prosperity of nations, and the recognition of which can alone render kingdoms secure and happy.

SOCIETY OF ENGINEER HE president, vice-president, number of members of the gineers, having just visited the Pr the opportunity was taken by the p Le Feuvre, C.E, FRGS, to M. Eugène, Flachst, presided Society of Civil Engineers. translation of the adress of the Society of Engineers, as fallen to me of presenting to" sident of the Society of Civil E At the t an address on behalf of the com siaty.

It becomes the subject of legitimate pride to our profession, that the more we reflect upon the peculiar features of our times, the more clearly we may discover the important influences brought to bear upon the enlightenment of nations by our labours. The mere contemplation of those stupendous and beautiful works with which the world has been enriched and adorned only within the last century, must have tended in a very great measure towards the elevation and refinement of society. In conjunction with

The

the uninspired passions of men, has been turned the repairing of the Atlantic cable of 1866, into a wilderness, where the fairer prospects of which has been recently injured in Trinity Bay. humanity have seemed blasted and destroyed. The Company's ship Chiltern" sailed for the But now we see the boundaries of nature every- Bay last week with the necessary machinery, and where yielding to the genius of inan. Abroad, an efficient staff. It is expected that the some are boring through mountains to make way "Chiltern" will arrive at Newfoundland by the for that swift messenger of civilisation, the loco- 15th instant, and we shall doubtless soon hear motive; others seek to connect vast seas, whose that the damage done by the only iceberg which uncontrolled and sudden union might even dis- appears to have touched either cable will be turb the equilibrium of our globe; some mount repaired. "Chiltern" has taken out a in air; others endeavour to accelerate the inter- quantity of spare cable to be left in Newfound. course between nations divided by measureless land, the Anglo-American Telegraph Company expanses of water; while extending around, and having decided that a reserve stock of cable, to encircling us on all sides, railways, viaducts, meet accidents, should be kept on the other side bridges, and magnificent structures of various of the Atlantic. The revenue of the Atlantic kinds go to make up a portion of what we are cable has not been in the least affected by one seeking to contribute to change the condi- cable breaking down, but it appears a want of tion of the world. We are architects whose mis- foresight not to have a proper vessel, with sion it is to repair the ravages of time and reno- machinery and officers, to watch over the only vate and preserve material things from decay. portion of the cables likely to be occasionally deranged by the icebergs which drift into Trinity Bay from the Polar current.

It is but due to those engaged in these labours, and to those especially who have obtained emi

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THE "FIELD" PATENT SAFETY
BOILER.

the flue. On the upper part of the inclined pipes
are formed a number of bosses, through which
holes are drilled above each of the Field

F and

the many classes of steam generator in

its equivalent are employed, there is none that more perfectly complies with the requirements of safety and thorough efficiency than does the ordinary Field boiler, now in such extensive use, and which possesses many advantages, already enumerated in the MECHANICS' MAGAZINE,* and not the least important of which is the great saving it effects in the amount of space occupied. Moreover, there is no limit to the extent of steam and water room which may be given, nor is there the slightest danger of explosion even in case of shortness of water. It is nevertheless an undeniable fact that much greater strength can be attained in a properly constructed boiler formed entirely of tubes than can possibly be had in a generator of which an outer shell or casing of comparatively large diameter is a component part. Hence, among many employers of steam power the first-named class of boiler would no doubt gain preference over one otherwise thoroughly efficient, effecting an enormous saving in space, but calculated only safely to withstand what are under ordinary circumstances considered high testing and working pressures. We believe it was in view of this fact that the proprietors of the Field boiler introduced the patent safety boiler, of which our present engraving represents a longitudinal vertical section in perspective, and which, as will be seen, is of the strictly" tubulous" class.

The furnace is constructed of brickwork in the ordinary manner, a large flue or chamber being formed at the back, into and through which the heated products of combustion pass to the chimney. Across this flue or chamber are placed a number of inclined cast-iron tubes connected by flanged joints with bolts and nuts, at their higher extremities to a longitudinal cast-iron tube constituting the main steam space. A corresponding

longitudinal cast-iron tube similarly connected to the lower ends of the inclined tabes, and protected by brickwork from the direct action of the products of combustion, serves as an equivalent for the water casing employed in the ordinary vertical Field boiler, and constitutes a receptacle for the collection and deposit of sediment. The under sides of the inclined cast-iron tubes have bosses cast upon them as shown, and tapering holes are bored, into which the wrought-iron Field tubes are drifted in such manner that they hang down into

See MECHANICS' MAGAZINE for July 14, 1865.

The

usual manner. These boilers are perfectly accessible for examination and repair, and as the different working parts are of the most simple construction, and very few in number, we are in. formed that these boilers can be produced ready for work at a very moderate cost, below that of other descriptions of tubulous generators, while the extremely effective character of the heating surface enables a very considerable saving to be effected in the length and weight of the boiler, and consequently also in the cost of setting.

The lightness of each of the various parts, combined with their simple construction, and the ease with which they may be put together in almost any situation, are important features, which render this boiler peculiarly suitable for transportation and erection in situations where it would be impossible to employ boilers of ordinary construction. Another point in favour of the Field safety boiler is, that it can be most readily enlarged by connecting additional series of tubes in cases where it is desired to increase the effective power of the boiler. The question of tubulous boilers is now attracting considerable attention, and the conviction is steadily gaining ground that it is the true system both for economy and safety. The manifold advantages embodied in the one we have been describing point to a success which we think it cannot fail to achieve.

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AMERICAN POLYTECHNIC INSTITUTE.

PRO

the depth of which A downward rush of the

ROFESSOR TILMAN, on taking the chair at a recent meeting of the Polytechnic, read a number of scientific items, from which we learn that, according to Sir C. Lyell, fish have been found in the artesian wells of the Sahara. They were brought from a depth of 175ft., and had perfect eyes. According to an opinion offered by Mr. Balfour Stewart, in a lecture before the Royal Institution, London, the spots on the sun's surface are produced by down. ward currents of the surrounding atmosphere, rather larger in diameter than had been estimated at not less the latter, thus affording ready means of access not only to them but likewise to atmosphere occasioned an exposure of the body other parts of the interior of the boiler. Each of the sun, and produced an appearance of a hole is covered with a tapering plug secured dark spot; an upward rush of the atmosphere in its position by two bolts and nuts. produced the bright feculæ that surround the radiation of heat is prevented by iron plates rest- dark spots, and are seen more conspicuously on ing on ledges above the inclined tubes, and the borders of the sun's disc. Asiatic cholera covered with ashes. Cast-iron plates are placed is said to be produced by animalcule, supposed across the upper and lower parts of the flue for to be a vegetable organism, owing to the great directing the costs of the products of combustion rapidity of the progress of the disease, so that they may impinge in the most efficient manner upon the Field tubes, the circulation of the water in which, as is well known, is of the most perfect character. Thus a much larger quantity of water is evaporated within a given space than is the case in boilers of other constructions, and almost the whole of the heat generated in the furnace (with the exception of what is necessarily employed for the purpose of maintaining a sufficient draught) is utilised in the production of steam.

Dr. Van der Weyde stated that he was long of opinion that the sun is a molten sphere, cooling imperceptibly, and that the spots are fissures in its side similar to those we see in masses of molten metal. He gave some interesting details of observations which were made for many years at Washington under the direction of the late Professor Bache, by which the exact form of the solar spots was drawn. By these observations it was discovered that the spots are much more angular than they appear even through the tele. This boiler possesses an advantage, the im scope. Referring to the statement that cholera portance of which can scarcely be over-esti- is produced by animalcule, he believed that it was mated, in doing away with that inevitable possible that it might be so. He instanced many defect of tubes fixed at both ends without effec- diseases produced by insects, visible only by tive provision for expansion and contraction the microscope. He showed also that animalnamely, leakage, the destructive effects of which cule entirely distinct from vegetable substances are well known. The means by which this result sprung up with amazing rapidity, as those that is attained have an important effect in simplify-produced the so-called phosphoresence of water, ing the construction and reducing the cost of the which is, in reality, the effect of an electrical boiler. Although we have already referred to discharge from these animals. the very perfect circulation of the water in the "Field" tubes, it may, nevertheless, not be out of place to remind our readers of the precise action which takes place. Upon lighting the fire, the consequent heating of the tubes immediately causes the water in them to commence circulating, every increment of heat, however trifling, added to the water contained in the annular spaces, between the inner and outer tubes, lessening its specific gravity, causing it to ascend, and cooler water to consequently descend the inner tubes to supply its place. This action goes on increasing gradually until ebullition commences, at which time the velocity of flow is increased enormously, owing to the great difference between the specific gravity of the mixed water and steam ascending in the annular the inner tubes. Sediment is carried up by the of May have realised an average of 50,000f. a day, The receipts at the Exhibition during the month spaces, and that of the solid water descending circulation in the "Field" tubes, and, aided in Numerous purchases for their respective museums without reckoning the payments for weekly tickets. the boiler under notice, by the excellent circu- are being made by Prussia, Austria, Russia, and lation in the inclined cast-iron tubes, is thrown other countries, and many of the most instructive to the bottom of the main water tube already and useful objects have been already secured by referred to, from whence it is blown off in the them.

Dr. Rowell, gave an account of a journey in the interior of China to a distance of 150 miles, performed entirely by water, which affords, in the Celestial Empire, the most convenient mode of locomotion. In place of canal locks the Chinese use mud slides, up which the boats are drawn by bamboo ropes.

Professor Tillman stated that a trial of the

strength of lead-encased block tin plates, the most satisfactory evidence was given of their strength. A conversation followed, in which very strong opinions were offered by the members as to the danger of drinking water poisoned by lead piping.

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