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LONDON: FRIDAY, OCTOBER 2, 1868.

ROLLING STOCK. No. I.

the entire body of the waggons are of that with on the North London Railway, which material. In connection with the alteration surpasses that exercised on the Metropolitan and improvement of goods waggons, there are line, although the latter is no mean rival. two principal points to be kept in view. The We shall return to this subject in a succeeding one is the reduction of the number of distinct article, and notice some of the minor accestypes or separate examples of construction, sories belonging to the extensive sphere emand the other that of an uniformity in the braced by rolling stock in general. weight carried by them. Both these arrangements are in some measure contingent upon the nature of the traffic to be conveyed, and depend upon the relative volume and weight of the contents of the waggon. Coals, for

instance, could not be carried in a cattle

truck, nor could the same weight of timber be WITH the exception of the locomotive, conveyed in a waggon which could be closely the greater part of the rolling stock of packed full of bricks. With a few exceptions, ways has not undergone any very radical the various specimens of goods carriages may ge since their first introduction. We be included under three chief heads, viz., the still close, stuffy first class carriages, common truck, which has no sides, but simply onless second classes, and thirds only fit a platform; the covered waggon; and the ttle and pigs. Some alterations have, coal truck, which has sides about 2ft. 6in. in er, from time to time, been made in not height. Whether the frames and the body of onl e carriages intended for the convey- the truck should be all in one, or detachable passengers, but also in those which at pleasure one from the other, is a matter of ropriated for goods traffic, and come detail best left to those engaged in their he various denominations of waggons, actual construction. No sooner was the orries, horse boxes, and other names problem of setting trains in motion by the to local districts. For some years, agency of steam once satisfactorily solved and engines have been turning their attention placed beyond a doubt, than a more difficult to rep' ing a large portion, if not all, the one, that of arresting their motion, arose in carriages and waggons by iron, and its place. It is not too much to assert that, the substitution cannot by any in spite of the innumerable patents taken out, e regarded as complete, yet a good inventions experimented upon, and trials unsuccess has attended their efforts. dergone, the question of obtaining a perfectly that carriages built principally of satisfactory brake action is yet an undecided ald be almost incombustible, has no one. Probably, the real reason why the ontributed to the favour with which difficulty has not been overcome, and the · material has been received. At the obstacle surmounted, is that too much has me, there are some objections to the been sought for, and too rigorous a solution al employment of metallic carriages, of the problem attempted. The end aimed at lly for those of the first class. Any by nearly all those striving to devise an o may have reasons, whether caused efficient brake has been one which is in reality health, nervousness, or general dislike foreign to the whole character of that mevelling, for making a journey by rail in chanical appliance. Inventors, as a rule, have ost comfortable manner possible, can do striven, with inexhaustible patience and assi"going first," and paying for the extra duity, to design a brake that will stop a train modation. Under these circumstances, almost instantaneously, and those who have valid or the person of nervous tempera- effected the change from rapid motion to a has a right to expect the maximum state of complete repose in the shortest time, int of ease and comfort compatible with have considered that they have approached exigencies and requirements of steam nearest to the vanquishing of the obstacle. motion. It is questionable whether these But in fact they were very far from attaining ditions could be ensured in carriages built the desired result. The great object of a gether of iron. Wood, appears to be brake is, not to suddenly and totally arrest the essary to deaden the jarring sound and progress of the train, but to gradually reduce ration, arising partly from the permanent it to a state of rest. It is not expected to act y and partly from the motion of the various only on rare and special emergencies, but to rts of the rolling stock itself. The combined be of continual use during the whole journey. stem of part iron and part wood is adopted on lines in France, Prussia, Belgium, and witzerland, and consists in constructing the ngitudinal frame pieces of iron, and the ross pieces and smaller scantlings of timber. The Lyons Company build their express arriages upon iron frames carried by ten wheels, which effects the double object of distributing the weight more evenly and preventing the overheating of the journals. Upon French lines, the distance between any pair of axles rarely exceeds 13ft., but the Prussian engineers fix their maximum distance at nearly 16ft., which is greater than that adopted upon any other railway. So far as the carriage is concerned, the distance between the axles, or between the points of support, is simply one of strength of framing, which can, by the employment of iron, be increased to almost any extent. But the matter is otherwise when the distribution of the weight is taken into consideration, and the chance of accidents, owing to the heating of the axle boxes. It is not an uncommon event upon our own lines, where the distance between the axles is far from reaching these dimensions, to witness the porters drenching with water the axle boxes of the carriage of a mail train during its temporary stoppage.

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In a word, it is for general, and not special, employment. In order to obtain a sudden arrest of motion, all the earlier, and most of the recent, descriptions of brake were made to lock the wheels immediately upon their application. Independently of the great impactive force suddenly brought into play, and the violent torsion thrown upon the axles by this arrangement, it is radically unsound in principle, and does not effect the result desired. If the skids press so tightly upon the wheels as to lock them, the train is not brought to rest so soon as if they only had bite sufficient to prevent them from revolving. The limit between the rotation and the sliding of the wheels is the one to be attained to, as it is well known that a body will slide faster than it will revolve. To determine theoretically the exact velocity at which a body will cease to roll and commence to slide, is a very nice mathematical problem, but practically the limits may be ascertained experimentally with sufficient accuracy for all working purposes. At the late Exposition, the improvements in the details of brake gear were mostly confined to effecting the instantaneous application of the skids to the wheels. These comprised the use of levers, screws, springs, balance weights, and other contrivances, including automatic and electrical agency, which have at different times been laid before our readers in these columns. Perhaps the best working system of brake power is to be met

T

TRINIDAD PETROLEUM.

HE vast deposits of pitch and asphalte which occur in the island of Trinidad have formed subjects for inquiry and experimental research for many years past, the object being to utilize them for various purposes. Prominent, if not foremost, amongst these experiments have been those which have reference to the production of light and heat. In our first number for the present year we printed an elaborate report from Dr. Anderson on the composition and gas-producing quality of Trinidad petroleum, in which it was demonstrated that this substance-bitumen from the Pitch Lake-might be successfully and profitably employed as a gas-producing material. With regard to the use of this substance as fuel, we have had many attempts to render it subservient to this purpose. The latest information upon this subject comes to us in the form of a dispatch from the Governor of Trinidad to the Duke of Buckingham, which details a series of successful experiments made on board H.M.S. "Gannet" with a new artificial fuel. The chief constituent of this fuel is petroleum or bitumen from the Pitch Lake, which is mixed with charcoal and moulded into bricks under pressure. The difficulty attending the use of the different asphalte fuels hitherto prepared has been that they have generally been found liable to adhere to the furnace bars, and also to run when exposed to high temperatures; these difficulties, however, appear now to have been overcome. From the interesting dispatch in question-which, we may observe, was forwarded to the secretary of the Society of Arts by order of the Board of Trade-we learn that some seven years since a gentleman in the island devised a method of preparing the fuel which insured the equal action of the fire upon all its particles, and obviated the above defects. This gentleman is since dead, but it appears that subsequently other experimenters in England, France, and Trinidad, simultaneously conceived a similar idea of utilizing the bitumen. The methods by which they attained their end varied, although the principle remained the same. Struck by this circumstance, the Governor directed the preparation of a few tons of fuel, placing the matter under the superintendence of a gentleman competent to deal with the question. The process of manufacture is very simple; the bitumen was mixed in certain proportions (not stated) with charcoal, the mixture was then ground, after which it was pressed dry into bricks 1ft. in length, 4in. in width, and 3in. in depth.

This fuel was tried on board the "Gannet " by Commander Chimmo, R.N., during a day's cruise, when she ran about thirty miles. At first, the engineer used coal and the asphalte fuel in equal quantities. The result, however, was not equal to that obtained with coal alone. Subsequently, the proportion of 35 per cent. of fuel and 65 per cent. of coal was adopted, and with this combination the engine duty was fully equal to that obtained with coal alone. The following is the report of the chief engineer of the "Gannet," which gives the details of the trial:- Primed laid fires, and got up steam, in port boiler, with patent fuel alone, quantity 10cwt.; time occupied in getting up steam, 1hr. 35min. Primed laid fires, and got up steam, starboard boiler, with equal portions of patent fuel and coals; quantity, 6cwt. of each; time in getting up steam, 50min. After steam being up, equal portions of patent fuel and coal were used in both boilers; proceeded

full speed, draught plates taken down; height of steam gauge, 10lb.; revolutions, 69; consumption, 7cwt. of patent fuel and 7cwt. of coal per hour; consumption, per indicated horse-power, per hour, 4.94lb. Fires cleaned out, using 60lb. of patent fuel to 112lb. of coal, took out two furnace bars in each furnace to allow a greater current of air, which was a decided improvement in the brightness of the fires; the pressure now rose to the proper working height, viz., 13lb., and kept steady; revolutions, 73; consumption per hour, 5ewt. of patent fuel, and 10cwt. of coal; consumption per indicated horse-power per hour, 4·35lb.; average consumption per indicated horse-power per hour of six different kinds of coals, 3.611b. No adhesion to the bars, except a small amount of clinker, which caused the fires to be raked about, thereby causing about 25 per cent. of ashes. The ashes consisted of half-burnt patent fuel. It is my opinion, if greater space be left between the furnace-bars, so as to admit a greater current of air, nearly the whole of the ashes would be consumed. The amount of smoke remained about the same as when using coal alone--if anything, rather less, and of a lighter colour, the deposit of soot over the average being about 6 per cent."

to Dr. B. H. Paul, who has paid special atten- upon the administration and progress of the
tion to the subject of artifical fuel. The Indian telegraph department for the years
report of that gentlemen is appended, and it 1862-3, 1863-4, 1864-5, 1865-6. "The tabu-
will be seen that he accounts for the dis- lar statements and details of operation which
crepancy in the rate of consumption of fuel took place previous to June, 1865, are com-
and cost, and suggests a means of increasing pilations from the records and reports ren-
the efficiency of the former. Says Dr. Paul, dered to my head office." "For them I take
"If this fuel can be delivered on board at half neither credit nor debit, for, as you are aware,
the cost of coal in Trinidad, it will probably previous to July, 1865, I not only had no con-
be useful. I would suggest, however, that nection with, but positively knew nothing
its utility might be increased if the large whatever of the working material, antece-
amount of earthy material in the pitch could dents, or organization of the department."
be separated in the manufacture of the fuel. Since Colonel Robinson's accession to office, a
This earthy material, which leaves an incom- total re-organization of the administrative
bustible ash, amounts to about 25 per cent., staff of the department has been effected, and
according to analysis I have made of the the following reforms carried out-the methods
Trinidad pitch, and it is to the presence of of transacting business and accounts have
this material that I should ascribe the differ- been greatly simplified, the administrative and
ence in the rate of consumption per indicated executive staff strengthened, a central office
horse-power, of the prepared fuel as compared of accounts organized and opened, a staff for
with coal, amouating to about three-quarters the examination and comparison of messages
of a pound per indicated horse-power per started, arrangements made for regular schools
hour." On the whole, we have a satisfactory of instruction, and sundry other changes.
case made out for this new fuel, and such a
one as warrants the application of machinery
to its manufacture. We hope to hear further
of this subject, which is as interesting as it is
important.

TELEGRAPHS IN INDIA.

It will be seen from the foregoing report that the defects to which we have before alluded were successfully overcome by the mode of preparation adopted by Governor Gordon. The fuel showed no sign of adhesion to the bars, nor of melting, and although a small amount of clinker was produced, it is stated to have been no greater than may often be found with ordinary steam coal. The conclusion, therefore, is that, in the proportions adopted by the Governor, an asphalte fuel may be safely and usefully employed, whilst as it can be delivered at Trinidad at half the price of coal, its employment-even in the proportions observed on board the "Gannet "would insure a considerable saving. But we have to remember that the furnaces of the Gannet " are particularly unsuited to the consumption of asphalte, which requires a strong draught to secure regularity of combustion. Further, the whole of the fuel employed on the trial referred to was made by hand, and was consequently wanting earth conductors, which are most destructive in that uniformity of texture which mechanito the maintenance of the electric charge.' cal pressure alone could insure. Hence it Other improvements-are changing the direc is but reasonable to suppose that under more tion of the line from Mogul Serai to Allahafavourable circumstances the proportion of bad, thus taking advantage of the railway asphalte fuel may be largely and advanbridges over the large river, dispensing with tageously increased. We cannot pass over For a long time past, we have been un- cables-and altering the direction of the the fact mentioned in the dispatch, that whilst acquainted with the actual state or pro- Assam line, shortening it by 120 miles-the -according to the chief engineer's report gress of the telegraphic system of our pos- commencement of reinsulating and duplicatthe consumption of mixed fuel per indicated sessions in India, beyond the fact of large ing the Bombay and Kurrachee line, changhorse-power per hour was on board the sums of money being spent in erection of tele- ing of offices, &c., and minor improvements. "Gannet " 4.35lb., the average consumption graphs; and also the constant complaints There are other improvements introduced, per indicated horse-power per hour of six coming to our ears of the telegraph generally tending to better the condition of the staff, different kinds of coal in the same furnace being not only badly erected but inefficiently and to make their position more comfortable. (but probably at sea with more wind than on worked. As our own system at home became the day of trial inside the Gulf of Paria, little by little united to the system in India, where it was nearly calm in the morning, and so that actually through transmission took where only a slight breeze blew in the after place, these complaints of bad working noon) was 3-611b., showing a deficit of 74, or became more tangible, until more accurate nearly three-quarters of a pound in the mixed details became known, and affairs arrived at fuel per horse-power per hour. If, how that peculiar state when they were bound to ever, the ashes which the engineers found mend. The date of this change for the and removed, and which consisted of half- better was in 1865, when the administration burnt asphalte fuel, had been burnt off, and of the telegraphic department in India besent through the chimney, which could be came re-organized, through the indefatigable done with a stronger draught, or more com- exertions of the new director-general, Colonel plete exclusion of all moisture by pressure Robinson, R.E., and into some of the imapplied by machinery, those three-quarters of provements organized by him, and of the a pound per indicated horse-power per hour state of the Indian telegraphic system, we would have been also utilized. In other wish to call the attention of our readers. words, the mixed fuel would have given the We have now in our hands certain papers same average as the six different kinds of relating to electric telegraphs in India, that coals mentioned. It is important also to notice that, contrary to expectation, the smoke produced by the fuel proved to be lighter in colour and less dense in volume than that of ordinary coal.

In speaking of the changes made during the nine months of his administration, Colonel Robinson, in his report (April, 1866), speaks of the following as being the most important of the changes inade:-The introduction of a new tariff based on the same principles that regulate the telegraphs of Europe. The introduction of stamps in lieu THE HE progress and development of tele- of money payment for telegrams. Putting graphy in our colonies is a matter of the lines of the Arracan divisions into a sergreat congratulation to the mother country. viceable state. Of the nature of the country As each year comes round, bringing with it through which these lines pass, Colonel the information of further and further exten- Robinson says:-"The physical difficulties sion of telegraphs in every direction, it can- of the country traversed are so abnormal not but bring with it much satisfaction that that positively no other means of communica our various colonies are following so well in tion except by telegraph exists. For about our footsteps, erecting telegraphs equally 120 miles the wire is carried through a dense efficient in their working and construction to forest almost entirely denuded of inour own. Year by year those extensions are habitants, but infested with wild beasts. going on; the arms of telegraphy in our The malaria is deadly; labour is exceedingly various colonies are now so extending that scarce: what there is, is most difficult to we may welcome ere long their junction, so procure. Numerous creeks abound which that all our colonies will then not only be can only be crossed by swimming. The telegraphically united to their mother country climate is so moist and warm that vegetation but also to each other. The means we have springs up in a manner almost marvellous, of becoming acquainted with the progress and the growth of plants and creepers is so made in telegraphy in our Australian colonies rapid that after clearance they speedily again has been usually derived from an interesting reach the wires, and thus form a series of series of annual reports prepared by the different superintendents of the respective colonies. As a rule, these reports have been generally of an exhaustive nature, giving full and complete details of the ise and progress of telegraphy.

The dispatch of Governor Gordon, together with the engineer's report, have been submitted by the secretary of the Society of Arts

On this point we again quote: These and sundry other apparently trifling changes, all tending to make the officers and signallers of the department feel that they are sure of considerate and liberal treatment, have already done an immensity of good. The scarcity of signallers that a year since bid fair to stop work altogether, no longer exists. Many of those officers who had left are anxious to rejoin the department, and the general tone of the department is such as to offer good prospects of future contentment and zealous industry."

By these and further recommendations being adopted, the condition of the Indian telegraph staff has been much improved, and nothing has tended more to that result than the manner in which the better executive have only lately been published by order of vacancies are filled up by sending properly the House of Commons. Amongst these educated persons from England. Colonel papers we find a most exhaustive report by Robinson's great and universal recommendaColonel Robinson on the administration of tion is to "make Europe your model, and I the telegraphic department. This report we therefore advocate a broad principle of welcome with some pleasure, as it places in striving to obtain those forms of telegraph our hands for the first time many important material which experience and the opinion details of the Indian system. The report is of European telegraph engineers have de

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clared to be the best adapted to the require-spectrum from the corona, and one of bright lines hours, for such collodion will stand less rough ments of India, rather than to experiment safe in saying that three of the lines in the spectrum plates, with all their troubles and uncertainfrom the prominence I examined. I am, I believe, treatment than bromo-iodized. Rapid dry with the invention of an Indian savan. Inof the protuberances correspond to C, D, and b. I deed, I attribute the bad working of the saw a line in the green near F, but I had lost so much ties, are at present out of the question in better Indian lines to a deviation from these time in finding the protuberance (owing to the finder astronomical photography, but there is no principles; in other words, to the department having changed its adjustment since last night), that reason why the glycerine process, which differs being inflicted with the Brooke bracket and I lost it in the sunlight before measuring it, and I so little from the ordinary wet method, should insulator, both of which are most thoroughly believe I saw traces of a line in the blue near G, but not be adopted. Practical experience with to see them clearly involves a very large change in unfit for the purpose for which they were the focus of the telescope, which was out of the the glycerine process has shown that the designed." The greater efficiency now exhi- question then. addition of a little organic matter to the glybited in the Indian service, the few comcerine bath improves the photographic quality plaints, and the better manner in which the of the resulting negative, honey dissolved in work is generally carried out, bear sufficient water and filtered being preferably used for testimony to the value of Colonel Robinson's the purpose. recommendations, and to the advantage that has accrued to the public from their being carried out.

sun.

I conclude that my result is, that the atmosphere of the sun is mainly of non-luminous (or faintly luminous) gas, at a short distance from the limb of the had to open the jaws a good deal to get what I could It may have had faintly luminous lines, but I see at first, and consequently the lines would be diffused somewhat; still I think I should have seen them. The prominence I examined was a very high The report before us gives us some in-narrow one, almost to my eye like a bit of the sun through a chink in brightness and colour (I could teresting details of the progress and extent see no tinge of colour), and somewhat zigzagged, like of the system; and fromthe statements given a flash of lightning. It must have been three minutes we are enabled to compile the following high, for it was on the preceding side of the sun near figures, giving the actual length of line and the vertex, and was a marked object, both in the last the annual progress:photo-plate just before the sun reappeared, and to the eye. Total length of line and offices open to Apr. 30, 1862 1862-63 Total number open 1863-64 during year 1864-65 1865-66

...

...

Line. Offices.

11,071 144

279 4334 1,485 120

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Captain Branfill saw the prominences coloured, as did two other gentlemen, but one in my observatory (like myself) only saw it white. I should, however, say, that for long I never saw a Orionis markedly red, nor Antares, and I may not catch red soon, 19 though I cannot conceive this being so.

2

9

*2

Total............ 13,390 176 During the above years the following deductions had been made-407 miles of line dis

mantled and thirty-three offices closed. This gives, then, the above figures as the state of the system on April 30, 1865 :-

Miles of line
Offices open

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13,390

176

Of this mileage we have the following subdivision:-There were 4 miles of 5 wires, 67 miles of 4 wires, 19 miles of 3 wires, 1,303 miles of 2 wires, and 11,996 of single wire. From this it will be seen that the communication throughcut India is almost entirely of a single wire.

Our space being limited this week, we defer until our next impression some further details relative to the cost of erecting and maintaining the telegraph system, and some statements as to receipts; also an analysis of interruptions, and their nature. We also hope to place before our readers some further information as to the staff and the part the mother country plays in supplying India with telegraphists and material."

THE PHOTOGRAPHING OF THE
GREAT ECLIPSE.

In conclusion, I may note that the darkness was very slight, and the colour not half so gloomy as in the eclipse of 1857, which was partial at Delhi, where I was then.

The most experienced and cleverest instantaneous photographer in London is Mr. Valentine Blanchard, who took the wellknown views in the City, wherein the persons walking in the streets, and omnibus horses with legs uplifted in the act of trotting, were all secured upon his very sensitive plates in the twinkling of an eye. Now, Mr. Blanchard always uses bromo-iodized collodion and iron development, whilst Mr. Warren De la Rue and Major Tennant use iodized collodion and pyrogallic acid development. Mr. Warren De la Rue abandoned iron development, because he found that negatives obtained with it had a granular structure when examined under the microscope, and when he adopted pyrogallic acid development he also used simply iodized collodion, which, as a rule, Although the photographic results of the ex-works best with such a developer. But much pedition are not so successful as were desired, depends upon the retarding acid, for Mr. some valuable experience has been gained. Sutton and other experimentalists now say Photography in the tropics is very different that one drop of pure monohydrated formic to photography in England, so much so that acid added as a restrainer instead of acetic manufacturers of photographic goods make acid to each ounce of pyrogallic developer, special apparatus and chemicals for use be- will make it act as rapidly as an iron deneath an Indian sun. Collodion of inferior veloper upon bromo-iodized collodion. quality rapidly becomes useless by exposure so, it would be a great advantage in astronoto tropical temperatures, and for use in those mical photography to use the latter collodion, regions collodion is commonly made with a as it will bear rough usage much better than larger proportion of alcohol and a minimum that which is simply iodized. Again, an iron quantity of ether, because of the rapid evadeveloper gives a very different kind of deporation in coating plates. The difficulties of posit, when either itself or the silver solution photography in the tropics are further aug- upon the plate contains organic matter. It mented by the liability of insects and dust to may be that these deposits are not granular get into the apparatus, and to settle upon the when examined under a microscope, and if so, prepared plates. Moreover, the heat tends one strong objection to the use of an iron to dry up the silver solution upon the plate, developer is removed. and to produce black spots in development.

In future, this last evil, which has so much troubled Major Tennant, can be altogether abolished in tropical photography. The operations of exciting and developing a plate are essentially distinct; in fact, there is no necessity whatever to keep such a very strong solution as 30 or 35 grains of nitrate of silver to the ounce upon the plate during exposure

OF the scanty details which have as yet and development. Two baths can be used
reached England respecting the expedi- in future, the one containing nitrate of silver
tions sent out to India by different European of the ordinary strength for the excitation of
governments, to observe or to photograph the plate, and the other a 10 or 12-grain so-
the great eclipse of the sun of August 18 lution only. The excitation of the plate can
last, the following news from Major J. F. be nearly completed in the first bath, and
Tennant, R.E., is of interest. Major Ten- then it should be immersed for about a minute
nant had the command of the English expe- in the second. Then, when the plate is
dition sent out to photograph the eclipse for placed in the dark slide, it will be covered
the Government of India, and the following with a solution one-third weaker than that on
news is an extract from a letter from him, the plates exposed by Major Tennant; con-
just received by Professor G. B. Airy, the sequently, the salt will be much longer in
Astronomer Royal, and dated Guntoor, crystallizing upon the film, so as to produce
August 18, 1868:-
spots. Development goes on much better,
This morning was very promising, and if it had especially in hot weather, when the plate is
followed the course of its predecessor we should covered with silver solution of considerably
have had a magnificent clear sky, but it clouded over less than half the ordinary strength.

If

There are, then, several questions which might be solved, and one difficulty which can most certainly be removed, respecting astronomical photography in the tropics. As the photographing of solar eclipses is sure in the future to prove an established branch of astronomy, there is room for plenty of experiments in the chemical and manipulatory branch of the subject, and such experiments

are worth making. The drying of the silver solution upon the film need never take place again. Why should not a sensible and clever practical man, like Mr. Blanchard, try his skill against an experienced astronomical photographer, to see which of the two can turn out pictures with the greatest rapidity and certainty with the same instrument? A series of experiments on this subject would be in the highest degree useful, because in the photographic world all pictures taken in less than a second are classed under the title of "instantaneous," so that what is really the most rapid process is not accurately known. Special instruments would have to be made to secure equality of conditions when trying the merits of different processes as regards

the east with thin cumulostrati, which, while hardly But a still further step can be taken rapidity and certainty, for the one quality is stopping vision, interfere very much with the photo-towards the preservation of the plate in good of littic use without the other.

graphic energy; and the result was that every nega

tive was under-exposed, and we have little more than condition under tropical temperatures. Glyvery dense marks showing the protuberances. The cerine may be added to the weak second bath six plates arranged for were duly exposed, but the just recommended, and then the plate will

corona,

Captain Branfill reports the protuberances unpolarized, and the corona strongly polarized everywhere in a plane passing through the centre of the sun.

ENGINEERING PAPERS.

LARGER than the satisfactory progress of

evidence of the

that besides showing but faint traces of any coron, keep in good condition for hours, without they are all covered with spots. Still we may make crystallization of the nitrate of silver. At something of them, and will try. least, in the hottest English summer weather, the body from which it emanates, comes the such plates will keep for five or six hours, volume of "Transactions of the Society of and a whole day in winter. All the other Engineers for 1867."* Since the last volume manipulations will be exactly the same as in came into our hands, the Society has underthe wet process. Probably, when a simply gone a change-decidedly for the better-in iodized collodion is used, without bromide, the plates will not keep so long as five or six

Complementarily I have to report a continuous

There were more offices closed than opened during

this year.

* E. and F. N. Spon, 48, Charing-cross. 1868.

its constitution. Our readers doubtless re- calculated for very heavy continuous traffic. subject of frame saws, their various modes of member the application of the members to This bridge affords an example of the diffi- attachment, and all the niceties of their conGovernment last year, for a Royal Charter, culties met with in the use of screw piles struction. This paper is illustrated by no in order that as they were becoming a large where the character of the river bed is not less than 18 folding plates, beautifully drawn body, and were accumulating funds, they properly ascertained in the first instance. It on stone, and which illustrate saws, tools, might protect themselves in a legal point of also shows the impediments to be expected in swing frames, sharpening machines, and, in view, and obtain powers for the better ad- the way of construction, where incompetent fact, everything pertaining to the subject of ministration of their affairs. This praise- or insufficiently informed persons will dictate mechanical saws. When we say that the worthy design, however, was opposed and to engineers what they shall put down. In author is the manufacturer of an immense ultimately defeated by the Institution of the present instance, the screws, designed by quantity of wood-working machinery, otá Civil Engineers upon-we are sorry to say, Mr. G. Wells, were altered by the enterprising readers will understand the practical nature for those who had to decide the matter-the gentleman who speculated in the erection of of his paper, which is as interesting as it is mere fact of alleged similarity of title. For the bridge. When they were being fixed they useful. our own part, we can see no similarity that could were found utterly useless, and, moreover, it possibly lead to a conflict of interests. How-was discovered that a different bed had to be ever, the application, after a spirited contest, dealt with than was at first supposed. This was negatived, and the matter would have been was purely the fault of the local engineer, who carried into the House of Commons had it reported too superficially on the subject. The not been for the discovery that an Act of first screws failed, and others were designed Parliament was already in existence, which by the author, which were of a gimlet shape, gave to the Society of Engineers all the and which, by dint of screwing and driving, powers it at present requires. This Act is were ultimately got home, not to make a very the Literary and Scientific Institutions Act, lasting foundation, we fear. 1854, 17 & 18 Vic., cap. 112, and the necessary steps have been taken to place the Society under this Act. This is a satisfactory step, which will tend to strengthen and consolidate the Society, by giving it facilities for the administration of its affairs which it did not previously possess.

Mr. Arthur Rigg, jun., next follows with a paper on the connection between the shape of heavy guns and their durability. He instances a great number of failures from guns giving way for want of the relief afforded by a heavy mass in receiving and absorbing the force of a blow. The greatest durability, he argues, will be associated with the heaviest breech, and he gives a number of examples of guns burst in the American war, to prove A paper on water, and its effects on steam his deduction well founded. Finally, we have boilers, from the pen of Mr. H. K. Bamber, Mr. Graham's paper on the most recent imfollows next, and which, with the discussion,provements in the injector. This useful affords users of steam power a considerable adjunct to steam boilers has undergone many amount of information upon a matter which changes and modifications since its first inoften gives them considerable trouble, as well troduction into England. It has now well as endangers the safety of steam boilers. We nigh reached that point when little more can next have a paper, by Mr. Henry Davey, be done to improve it, and some very excelupon pumping engines for town water supply. lent examples are described and illustrated Mr. Davey gives a design for an engine for by the author. But, with all its efficiency and this purpose. The discussion turned upon the simplicity, there are still those who prefer the relative economy of the Cornish single-acting pump, but we cannot help thinking that their engine, and of the rotary engine. Mr. Baldwin prejudices will die out in course of time, as Latham, the present president of the Society, they see the injector steadily coming into in support of the Cornish type, instanced forty- almost universal use. seven examples at as many waterworks, where the economy was surprising. Other speakers upheld the rotary engine, and instanced points of superiority, especially that of first cost.

Turning to the literary portion of the thick volume before us, we find nine valuable and practical papers, and the discussions thereon, besides an interesting address from the president. Out of these nine papers four have been adjudged premiums of books, viz., Mr. S. W. Worssam's paper on mechanical saws; Mr. A. Rigg's paper on the connection between the shape of heavy guns and It will be perceived from the foregoing their durability; Mr. J. Gresham's paper on notice that the "Transactions of the Society the most recent improvements in the injector; of Engineers " is a most valuable annual and Mr. Ewing Matheson's paper on the addition to our engineering literature. It quality of cast iron as at present used. With Following Mr. Davey's paper is one of affords information for various branches of regard to the papers generally, we may ob- special interest on water tube boilers, by Mr. the profession, and is no whit behind its preserve that having been enabled, by the cour- Vaughan Pendred. The author enters very decessors in practical value to all. As far tesy of the Society, to publish them, some-extensively into the subject of this special as mere bulk goes, it is an improvement upon times in abstract and sometimes in extenso, class of boilers. He first considers the general what has gone before, whilst the paper, printwith engravings, our readers will, for the most principles to be observed in their construc-ing, and lithographic drawings-especially part, have made themselves familiar with tion. He then alludes to the history of these the latter-reflect credit upon the publishers, them. On the other hand, nine months have boilers, selecting for description and illustra- who know so well how to produce this class elapsed since the last paper in the volume tion examples of the various classes. Those of publications. As we have already stated, appeared in our pages. Not only is this boilers of modern construction, containing the "Transactions" indicate the healthy and time long enough for some of the subjects to the most recent improvements, and giving the prosperous condition of the Society. We are have passed out of mind, but it has, we are best results in practical use, are prominently glad to bear testimony to its increasing popu happy to say, introduced us to a number of brought forward by Mr. Pendred. Amongst larity, and to the fact that its numerical new readers, so that a resumé of these papers others, we may mention those of Howard, strength continues to improve. The change will doubtless prove alike welcome to all. Alban, Galloway, Martin, and Field. These it has recently undergone in the elevation of We first have the inaugural address of the are all fully described and illustrated. Al- its social status, combined with the unity and president for 1867, Mr. W. H. Le Feuvre, in together, this paper will compare well with fellowship of all its members, renders it easy which, amongst many generalities incident to any others read before the Society, and, if we to predict for it a future of increasing honour such an address, he ably points to some de- are rightly informed, the author would have and usefulness. fects in various departments of engineering had a premium awarded him had it not been and applied science, and suggests remedies for the circumstance of his being a member and improvements. The address contains of the council of the Society, and therefore many remarks which possess a more than debarred by the rules from receiving a pretransient interest, and which those who take mium. the lead in social and scientific advancement A very practical paper, and one of import- THE exports of railway iron from the United Kingdom amounted in July to 37,516 tons, will do well to study. The first paper is by ance to engineers, next follows; it is by Mr. as compared with 66,101 tons in July 1867, and Mr. Thomas Baldwin, who has carefully in- E. Matheson, upon the quality of iron as now 53,256 tons in July, 1866. The falling off obvestigated the nature and action of safety-used. The writer, who is a manufacturer, servable in the exports in July was attributable valves, and has embodied in his paper the points out how engineers differ in their to the diminished demand for British India. As valuable practical results of his researches. opinions as to the quality of iron. He gives regards the exports for the seven months ending The subject led to a warm discussion, in a great deal of information upon the subject, July 31, this year, the total amounted to 334,056 which various opinions were given, and a which was enlarged upon in the discussion. tons, as compared with 318,028 tons in the first number of safety-valves were described, one Mr. Matheson's paper is well worthy the seven months of 1867, and 312,723 tons in the member alone introducing no less than four attention of engineers engaged in constructive Russia to July 31, this year, declined to 28,100 first seven months of 1868. The exports to to notice. It was admitted on all hands that works, who will find some valuable hints upon tons, it was of the first importance that a valve the subject of the universally used material-corresponding period of 1867, and 38,261 tons as compared with 48,432 tons in the should be so constructed and placed as that iron. in the corresponding period of 1866. To the it could not get out of order, and could not An exhaustive paper upon mechanical saws, United States, however, the shipments ma be tampered with. Such a valve is that of by Mr. S. W. Worssam, jun., follows. The amounted to 165,480 tons, as compared with Mr. Naylor, which is fast coming into exten-author, in the first part, touches upon the 112,661 tons and 60,979 tons respectively. British sive use, and which we think is one of the history and origin of mill saws, after which India absorbed 51,026 tons in the first seven very few that are really entitled to be called he describes the various forms of saw teeth in months of the year, as compared with 83,473 'safety valves." general use. He then proceeds to a considera-tons and 78,381 tons respectively. The value of We next have a paper upon the application tion of all the tools and apparatus used in the railway iron exported in July was £300,344, of screw piles to bridges, the example selected sharpening and setting saws, introducing us £420,130 in July, 1866; and for the seven months as compared with £556,099 in July, 1867, and by the author, Mr. J. G. Horner, being a to many a wrinkle in this respect. The wrought-iron girder bridge at Verona. In second part of the paper opens with a notice pared with £2,662,380 and £2,539,483 respecending July 31, this year, £2,614,606, as comthis paper we have a description and drawings of the various machines in use for sharpening tively in the corresponding periods of 1867 and of a light and useful bridge, although one not saws. The author then carries us on to the 1866.

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EXPORTS OF RAILWAY IRON.

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