THE MECHANICS' MAGAZINE. LONDON: FRIDAY, FEBRUARY 15, 1867. OUR NATIONAL DEFENCES. be instituted as to whether a return to the mated at thirty-six miles, and the cost per TELEGRAPHY IN NEW SOUTH ney. It is stated that the lines as a whole worked very satisfactorily throughout the year, with few exceptions on the Western Line, Grafton and the Kiandra branches; the former caused by clearing for the construction of the railway over the Blue Mountains, whereby the telegraph line received considerable damage from falling trees, and the two latter from floods, snow storms, and other unavoidable accidents. In considering the advisability for a line from Tamworth to Fort Bourke, and its continuation down the Darling River to Wentworth, T will be well within the recollection of our and, in fact, all the future extensions, Mr. readers that we were the first to call pubCracknell observes that whilst there was a lic attention to the defective mechanical falling off of 20 per cent. on the aggregate construction of the Armstrong gun, to report telegraphic business from the stations on the the trials that have taken place and the nature Gold Fields, the stations in the pastoral disof the failures, and to point out that, however tricts exhibited a considerable increase, which extravagant the national outlay, under no possiHE progress of our Australian coslonie is very encouraging for extending the lines on ble circumstances could this gun remain in the has been so marked and so rapid as to the guarantee principle to the pastoral disservice, owing to its inherent defects. The Go- call forth the admiration of all who have con- tricts, such as Fort Bourke. The value of vernment for the time being in the House of sidered the matter. This progress is strik- such means of communication cannot be over Commons, through Mr. Baring, the then under ingly indicated by the construction of a system estimated, and the whole cost of the entire line Secretary of State for War, impugned and ani- of railways, which is still extending itself, and would be more than covered by the saving of madverted on our statements in the strongest the adoption of the electric telegraph, which valuable property during a single flood, as interms. Nevertheless every one of them has is becoming general throughout the country. formation would be rapidly conveyed to the proved true, and the Armstrong gun is virtu- Telegraphy has not become so common in our several stations down the river, when the ally out of the service. They are being as own country that we cannot receive with in-waters are dangerously high on the tributaries rapidly as possible converted from breech- terest information respecting its progress in of the Darling, communicated with by the loaders to muzzle-loaders, by re-lining the far-off lands. On the contrary, we gladly existing lines. The guaranteed lines are in guns and closing up the breech end by mas- accept particulars of the mighty though a very satisfactory condition, as appears by sive screws. The cost of this experiment to subtle agent of peace and civilisation which is the following financial statement:-On the the country has been in round numbers four gradually weaving a wire network over the line from Wellington to Dubbo, the revenue exmillions of money! We have no hesitation in whole face of the earth. It crosses and re-ceeded the working expenses by £113 14s. 2d., saying that had the Government possessed at crosses our lands, it traverses and re-traverses and on the line from Deniliquin to Hay by the time competent advisers, such as were old Ocean vieing with thought in its rapidity of £14 11s. 4d. £128 5s. 6d. From Braidwood the members of the old Ordnance Select Com-action and literally annihilating time in its work- to Queanbeyan the working expenses were mittee under General Cator, who, by the way, ing. The latest telegraphic intelligence from £24 93. 10d. in excess of revenue, whilst from were unpaid, and who resigned rather than New South Wales is embodied in a report re- Queanbeyan to Cooma they were £3 18s. 10d= recommend the adoption of the Armstrong cently received from Mr. E. C. Cracknell, the £28 8s. 8d., thus showing a profit of breech-loading gun, such a fearful waste of Superintendent of Electric Telegraphs at Syd- £99 16s. 10d. public money and such a loss of valuable time The report is for the year 1865, and includes would never have occurred. Having pre-half of the last year up to June 30. In 1864 mised thus far, we would seek to draw the the extension from Murrurundi to Mudgee a earliest attention of every thinking man to the was in progress, and was completed in April, still greater waste of public money which has 1865; the total cost of construction being been and is still being perpetrated. £5,116 33. 6d. On this line a station was The late Premier, Lord Palmerston, with opened at Cassilis on April 26, 1865, and statesmanlike sagacity, in a masterly speech another at Merriwa, on October 6, 1865. This in the House of Commons, laid before the na-extension, as anticipated, has proved a valution its utter defencelessness. The nation re-able addition to the existing line to the north, sponded as one man to the appeal, and some and has, on several occasions, been the only eleven millions of money were voted for the channel of communication for the rapidly inpurpose of defending our arsenals and dock-creasing business with the colony of Queensyards. Now the question to which we seek to land and the northern stations in the colony draw earnest attention is, How has this money of New South Wales, when, from floods and been spent? We have taken the pains to other causes, the direct line between Sydney visit the defensive works at Portsmouth, Ply- and Murrurundi has been rendered unavailmouth, Pembroke, Liverpool, and the deable. The line from Queanbeyan to Cooma, fences of the Bristol Channel, Dover, &c., which has been carried out on the guarantee and we have no hesitation in saying that, as principle, was completed in September, 1865, opposed to modern artillery, they are almost and a station was opened at the latter place worse than useless. The responsible officers on October 9 following, the total cost being of the War Department, to our knowledge, for £2,839 1s. 9d., and the distance sixty-four the last seven years have been in possession miles. A station was also opened at Jerelof plans for iron fortifications; yet to this day, derie, on the Deniliquin line, on May 4, 1866, they have never even caused an experi- the inhabitants having given the usual ment to be tried upon a model fortification entirely of iron. On the contrary, With regard to the lines in progress, we they have persisted in spending thousands gather from Mr. Cracknell's report that the upon thousands in the hopeless attempt to extension between Deniliquin and South Auscombine iron embrasures with brickwork and tralia has progressed very slowly, in consegranitework, with what result our number for quence of the drought, and difficulties the December 1, 1865,* testifies, ten shot being contractor has experienced in obtaining carsufficient to utterly ruin one of their pet riage for the necessary material, but the recent constructions, erected at the cost of many rise in the Murray in that district has enabled thousands. We have much pleasure in re-him to get the wire, insulators, &c., on the producing, on page 99 of our present issue, ground. At the time the report was written an important and interesting article from the July, 1866-there were seventy-five miles of Standard of the 5th inst. upon the subject, lines erected, with sixty-five miles of poles and to which we desire to direct especial ready to receive the wire, and it was expected attention. We sincerely trust that a sub- that the whole would be completed in the ject of such great national interest and course of a few months. That portion of it importanee will receive the earliest atten- completed between Deniliquin and Moulamein tion of the members of the House of Com- had been inspected, and a station was opened mons. We hope that no time may be at the latter place on the May 9th, 1866. lost in investigating the public expenditure in There were several extensions proposed. The reference to this matter, and in ascertaining report states that a guarantee bond has been whether the present highly paid Ordnance Se-entered into by the inhabitants of Burrowa, for lect Committee do efficiently and properly the extension of the line to that place, and a fulfils its duties. Further, an inquiry should tender has been accepted for the completion of the line in three months; the distance is esti * Article, Granite and Iron Fortifications. guarantee. Many of the posts on the Kiandra Branch between Tumut and Kiandra are in a very unsatisfactory state, the line requiring a thorough repair, and the greater portion re-poling. A section of this line, it will be remembered, was erected during the first rush to the Kiandra goldfields, under the direction of the chief commissioner for the southern goldfields, for the purpose of guide-poles through the deep snow-drifts in that locality. If we turn to the question of revenue and expenditure, we find that the receipts exhibit a satisfactory increase over the previous year to the amount of £1,683 17s. 1d., and an increase of 8,285 messages, proving that the business of the department is still steadily progressing, and that the public appreciation of the facilities afforded by telegraphic communication is annually more apparent. Some information respecting lines in other colonies is afforded by the report, and which was supplied by Mr. M'Gowan, the General Superintendent of Telegraphs in Victoria, and Mr. Todd, Observer and Superintendent of Telegraphs, Adelaide. In Victoria, the number of messages transmitted for the year ending December 31, 1865, was 279,791, and the number of miles of wire open, was 3,109. The new stations opened, were St. Arnaud, Seymour, Jamieson, Casterton, Malmsbury, Wood's Point, Collingwood; also offices at railway stations, Runnymede and Echuca. In South Australia, the number of messages during 1865 was 106,874. During the year, stations were opened at Milang, Victor-Harbour, Blanche-town, and Moonta; in January, 1866, at Lyndock, Tannuda, and Waterville. The report of the Superintendent of Telegraphs in Queensiand states that the number of miles opened was 1,1314, and that the extension to Bowen was being proceeded with, and was expected to be completed in abou THE FOREIGN MANURES. four months. We may therefore congratu- number of oxen for the sake of their skins those who might otherwise be compelled to late our colonial friends, upon the extension and suet, the remaining portion of the carcase go in a state ill protected from the cold. and increasing application of the telegraphic being thrown away as valueless. In addition Shoddy, as hitherto made from woollen rags, system, which gives the surest indication of to these, there are also the remains of the has been but little removed from a kind of healthiness and commercial prosperity. animals killed for food, and it is calculated fluffy, woollen dust, the length of the best fibre that during the entire year there is wasted in it scarcely exceeding half an inch, the bulk upwards of 4,000 tons of material admirably being very much shorter and much of it absoadapted for the manufacture of artificial lute dust. This arose from the defective mamanure. The bones are to some extent col-chine which produced it. Certainly the usual lected and despatched to England and France, machine is simple, but not very effective as HE principle of assimilation, by the aid but in consequence of the high export duty to excellence of product. of which any member of the animal or and the infectious nature of the material, it is The general principle and working of the vegetable kingdom converts to its use the difficult to find the means of transport, except machine is this. The rags being cleaned and especial natural elements calculated to pro- at a price which the cargo could not afford to torn or cut into convenient-sized pieces, are mote its growth and development, and rejects pay for. Thus they are frequently left to placed on an endless band, which carries them those unsuitable for that purpose, combined accumulate to a considerable and often danger- to a pair of fluted rollers, by which they are with the universal law of reproduction, ous extent. France as well as England seized and held tightly and gradually proforms the basis for the theory of manures. imports large quantities of Peruvian and truded on the other side, where a cylinder full The chemistry of vegetable life is even at the African guano, which does not contain on an of spikes revolves at a great speed, rapidly tearpresent day but little understood, although the average more than 10 per cent. of nitrogen ing or rasping the rags as they are protruded time is undoubtedly arrived when we seek to and 14 of phosphate salts. The composition into broken fibre. With some kinds of woolknow the reason of everything, and are no of the new manure, as prepared by M. len rags, perhaps very little better results can be longer content to neglect the cause because the Pitancier, at Odessa, is, quoting from our con- obtained with any machine; but from all looseeffect is an everyday occurrence. Carbonic acid, temporary Le Génie Industriel, as follows:-ly woven fabrics, such as flannel and most water, and ammonia are the inorganic con- Pulverised bone containing seventy-five parts woollen fabrics for ladies' wear, fibre of from stituents present in the atmosphere, tending to of nitrogen in a thousand; dried blood con- two to three or even four inches might be obaid the development of plants, and the taining 170 parts; leather parings, 93 parts; tained with a suitable machine, and such peculiar benefit accruing to them from the woollen rags, 202 parts; muscular flesh, 138; might be easily re-spun without the addition application of the latter ingredient is an in- horns of sheep and oxen containing 157 parts, of any new wool, and this, in fact, is done by a dubitable explanation of the reason of its and what might be termed odds and ends, newly invented machine which we have had presence in the air surrounding us. Manures making up another 302 equivalents of nitrogen. the pleasure of inspecting at rest and in action. undoubtedly owe a great portion of the effect The whole of these materials, after being This machine is equally applicable to the unthey produce to the presence of phosphates reduced to a minute state of division, are dried ravelling of silk rags, which the shoddy maand alkaline salts; yet the ammonia certainly in a furnace and mixed with a small proportion chine is not competent to do, nor indeed has plays the principal part in bringing about of animal and vegetable charcoal to reveal We will give a general description of this mait been accomplished by any other machine. the result. For many years past guano, or the occurrence of putrefaction. It is well huano, has been imported in enormous quanti-known that some manures become exhausted chine, which we are only permitted at present ties into this country from the sterile and so rapidly that the plant has not time to arrive to do; seeing that there are several particulars uninhabited isles of the western coast of South to maturity before the fertilising properties in its construction which are not yet secured America. The fertilising property of ammonia disappear, while others act too slowly and there- to the inventor. is due to the presence of azote or nitrogen in its fore never endow the plant with real nourish- It consists of a series of jointed brushes composition, which is chemically represented ment. M. Pitancier considers that the com- moving in quasi-elliptical guides, on which the by the symbol N H3. Hence the great position of his manure is calculated to obviate rags are placed, being first cut into suitable advantage of applying it to wheat and cereal both these disadvantages, and although notice pieces. On these brushes, they are carried crops, which require a large supply of that has only been taken of the quantity of under a cylindrical brush which turns at element. The guano imported into England nitrogen in its manufacture, yet the nature greater speed than the jointed brushes move, and is usually of a light brown tint interspersed of the ingredients demonstrates that there thus keeps the rags straight; behind this brush with yellowish specks; it dissolves with 18 a larger percentage of other valuable there is a wooden cylinder armed with steel facility in water, and the solution contains salts, such as phosphates and carbonates, teeth, which catch the threads of the woof large quantities of oxalate of ammonia. It available for its purpose. The guano which and remove them from the warp, and then was discovered in the analysation of this sub-arrives at Havre costs on delivery from deliver them on to a second cylindrical brush, stance that it possessed a peculiar ingredient 11s. to 12s. per cwt., while the manure from which in its turn delivers them on the disto which the name of guanine was given, and Odessa can be delivered for 7s. per cwt. charge roller, from which they fall, if it be which is represented by the symbol of C10 Hs at the port of Marseilles. silk, in large flakes, the warp remaining on Ns O2. It has precisely the same constituents The erection of the premises necessary for the jointed brushes in long fleecy fibres, from as xanthic oxide, although the proportions are carrying on this business costs about £12,000, which it is also removed as it comes round to different, the composition of the latter being and, as may be anticipated, employs steam as the discharge point. The fibre obtained from represented by C5 H2 N2 O2. The connection the motive power for all the machinery in silk rags is in every way equal to that from between these two substances consists in their action. In order also to utilise the woollen which ordinary spun-silk is made, and will both being closely related to uric acid, which and cotton rags to the full extent, machinery doubtless be used for the same purposes, and in an impure state forms the principal com- has been set up for the purpose of converting for the warp of ordinary silk with thrown silk ponent of guano. Viewed in this important the quantity not used in the manufacturing for the woof. In operating on mixed fabrics, light it is worth noticing that uric acid has of manure into unbleached paper which is ex- whether woollen or silk, where the fibre of the never been prepared by artificial means, but ported into France to be finished. In collect- material is not mixed and spun together, but is a distinct product of animal organisation. ing the bones for the manufacturing process, where the commoner material is used for the Its composition is C10 N4 O, H2 2 H O, and many of them are selected and set aside for warp and the better for the woof, this mawhen distilled yields among other ingredients the purpose of furnishing the toy trade; the chine effectually separates the two materials, a dark substance containing a large quantity fat is retained for making soap, and the oil of the woof being removed in fleecy flakes, of nitrogen, to which it probably owes a large the hoofs for the wants of the inhabitants, for while the warp remains attached to the jointed portion of its valuable qualities. Although the production of gelatine and size. Thus brushes. We saw several examples of this, uric acid may not be capable of artificial nothing appears to be lost, and we trust that where the fabrics were of cotton and silk, and preparation, yet there are abundant of the establishment will prove remunerative to cotton and woollen. In both cases the cotton the proprietor, and an example to others of warp was left perfectly intact, and the silk and what can be done in similar situations. wool were perfectly removed without in the least breaking the fibre. 5 manures, valuable and effective, which can be 80 prepared. According to the law of reproduction the decay and putrefaction of animal and vegetable life is made subservient to the growth and development of fresh examples, and thus in manufacturing artificial manures we somewhat naturally expect them to be composed, if not of the remains of the dead, at least of those productions for which the living have no further use. On the plains of Australia sheep are killed for the sake of their wool alone, and on the prairies of America the carcases of countless buffaloes and wild cattle bear witness to the enormous loss of what might be rendered available both as food and manure. Recently a manufactory has been established at Odessa for the production of an artificial manure rich in nitrogen and the phosphate salts. In this city are annually slaughtered a considerable The machine we saw in operation we understand will produce about 1201b. of silk from the rags in a day by the simple attendance of THE "SHODDY DEVIL" SUPERSEDED. one boy or girl to feed it, and a one-horse HE term "shoddy" has now been so long steam-engine will drive three of them. The THE in use that it has acquired a secondary silk rags, we were told, can be bought at premeaning (at least with our cousins the Yan- sent for about d. per pound; but about half kees, for their mushroom millionaires). Here of the weight is waste, being simply dirt or seams in England, we mean by it woollen rags torn and other parts of old garments which cannot and clawed into fibre, to be used over again be used. This raises the price to a penny by being spun with new wool and woven into common cloth, thus turning that to a profitable use which would have been otherwise entire waste. It is true that cloth made from shoddy cannot boast any great excellence as to strength and durability; but it is cheap, and will serve as a covering at a cheap rate to only. The charges that come against it are for assorting the rags, cutting into suitable sizes, washing, feeding the machines, and driving power. These charges are all comparatively light, seeing that no skilled labour is required. The profits must consequently be very great, when such a valuable product THE B OF AIR. as raw silk is picked up as it were out of the PURIFICATION AND REFRIGERATION passes into the locality assigned to it. In the very gutters; such rags having been considered event of the sponges being worn out or their till now as of no value. We were allowed to number incomplete, it would be possible to manipulate the machine ourselves, and, having N the ventilation of any space devoted to substitute pressed wool, hair, or any other the use of human beings two conditions substance which would serve the purpose of an placed some pieces of silk rag on the hinged brushes, we had the pleasure of seeing thrown are necessary to be fulfilled in order to ensure air filter, but the result would not be so satisout at the other end of the machine, a Jarge that invaluable benefit being fully bestowed factory as where the sponges were used. The flake of fine fleecy silk, the fibres in which we upon the occupiers. One is that there should box enclosing the sponges has no bottom, and found to be from 2in. to 6in. in length, agree-supply of fresh pure air, and the other that the the air enters, by a pipe to a ventilator, which be not only an adequate but an abundant is connected, on the side opposite to that where ing in lengths with the various pieces of rag vitiated air should be thoroughly and con- draws in the air and compels it to pass through which we introduced, clearly showing that the office the machine performs is simply unravel- tinually abstracted. Provided that the com- the sponges. After it has traversed the sponges, ling, but not at all injuring the fibre. Its monest means of ventilation be attended to, it or filter, as it may be termed, and is cooled operations on woollen rags are equally successis a very simple matter to ensure these require- down, and perfumed also, if required, it is ful, but we have laid more stress on the un-ments, but it is notorious that these means are ejected into the desired locality, whether an ravelling of silk, it being the more difficult universally neglected. The question of sup-ordinary room, a theatre, a church, or ship, as of the two, and not having before been done. plying fresh air is not confined solely to the the case may be. The sponges are maintained This machine is at present only exhibited pri- renewal of the quantity suitable for respira- in a state of moisture by the arrangement of a vately for reasons before stated. We hope in tion, but it also embraces the supply relating number of small tubes, pierced with holes, time to be able to give a fuller account of it to hot air pipes or other methods suitable for and which inject upon them the liquid obwith drawings. maintaining the temperature of any room or tained from a small reservoir. By a mixture building at a fixed standard. Although em- of certain chemical salts it is well known that ployed with decided success in numbers of a most intense cold can be produced, and public places of recreation and instruction, the therefore by saturating the sponges with a principle of heating by hot air has never been solution of a freezing mixture, the air could be introduced into private dwellings, and the open cooled en passant to almost any degree of temfire-place still forms the prominent feature of perature. The principle of all frigorific mixour domestic hearth. Undoubtedly many of tures depends upon the liquefaction of any the plans in use at present are too expensive solid substance or substances by virtue of a to be employed on a small scale, and others weak chemical affinity and the conversion of a are troublesome and uncertain in action. large amount of sensible into latent heat. Again, in warmer latitudes it is equally de- Thus, if powdered ice or snow be mixed with sirable to cool the temperature of the air, and common salt, chloride of sodium, liquefaction only those who have experienced the sensation ensues, and the mercury in a thermometer can appreciate the feeling of relief afforded by plunged into the mixture falls rapidly to 0 deg. the advent of the cool breeze, which in tro- Fah. Also, if powdered crystallised chloride of pical climates succeeds to the burning heat of lime be mixed with snow, the cold produced is so the day. The annexed cut represents an ap- intense as to freeze mercury, which does not conparatus for effecting the object designated by geal until the temperature sinks to 40 deg. the heading of our subject, and the advan- below zero of the Centigrade scale. In the tages claimed by its inventor, M. Cabanes, are cut, fig. 1 represents an elevation, and fig. 2 the following:-The complete purification of a horizontal section through the line 1 and 2 the air and its cooling down to any desired of the apparatus, which consists of the box or temperature. A facility of erection, com- frame C, which encloses an inner case of wire bined with a small first cost, and the opportu- gauze with large meshes, carrying the sponges. nity, if desirable, of saturating the air with The tubes t t serve to distribute the liquid over their surface, and are connected by the cock T with the reservoir R. The side of the case opposite to that where the pipes are placed communicates with the ventilator V, and draws in the air through the orifices a (see fig. 2). The apparatus is set in motion by means of the pulley P, and draws in the air, forcing it to pass in its outward course through the sponges. As these latter are very apt to become clogged, springs b b are inserted in the inner case, which keep the air passage open. The superfluous liquid which drops from the sponges passes away through a small pipe d. The most advantageous motive power to be employed depends altogether upon the peculiar circumstances attending each special case. Unless where the apparatus was intended to be used on a very extensive scale, any ordinary motive agent might be rendered available-even hand power might be sufficient, This consideration is, however, of very secondary importance, as in all localities where it would prove advantageous, ample means for maintaining it in action would be on the spot. THE TUNING-FORK AS A REGULATOR OF MOTIVE POWER. THE tuning-fork has frequently been employed to measure minute intervals of time. M. Duhamel and many philosophers after him adopted the instrument for this purpose. With this object M. Brequet now proposes to prolong indefinitely the vibration of a tuning-fork by means of clockwork. He has constructed some apparatus for this purpose, which is described in the Comptes Rendus as being arranged similarly to an ordinary clock of two parts-a train of wheels and an apparatus with isochronous oscillations yielding to a reciprocating action through the medium of an escapement. The tuning-fork regulates the running of the train; the train gives to the tuning-fork at each vibration a slight impulse necessary to prolong its oscillating movement. The train, by means of indices carried upon the axles and turning in front of the dial, enables the vibrations of the tuning-fork to be counted. The more precise method of controlling the regularity of the movement of an instrument of this kind consists in the comparison of a regulating tuningfork with a free one by the optical process of M. Zenagous. By this process M. Brequet was enabled to ascertain the persistence of harmony once established between these two tuning-forks, the free instrument being put in vibration by the hand each time it is desired to renew the comparison. The harmony is still maintained when the moving weight of the apparatus is doubled or trebled. FIG.I. The instrument first employed by M. Brequet made about one hundred vibrations (fty double) per second. He, however, subsequently tried another making about two hundred simple vibrations per second, and the apparatus has worked without any change having to be made. M. Brequet regards it as certain that we shall be able to apply to the instrument some much higher-pitched tuningforks by conveniently diminishing the dimensions of the escapement. It will be readily understood that in placing upon the two branches of the key two equal and symmetrical masses we can diminish the rapidity of the vibrations, and it is easy to conceive dispositions which would permit the passing any odoriferous substance. It is more than through all speeds between two extreme probable that, except in the case of a sick or in limits. The results of his researches on this fected chamber, the faculty would set their subject lead M. Brequet to believe that the faces against this last-mentioned advantage. principle of this instrument can be utilised for But not only legends of foreign lands, the chronoscopic experiments such as are required fables of Oriental romance, but the actual testo measure or appreciate very small fractions timony of travellers and those who "go down of time. It will also serve to give an uniform to the sea in ships," leave the fact indisputmovement to different apparatus for registra- able that, except in our northern climates, the tion or observation which are employed in the sciences. And lastly, it will enable us to obtain the synchronism of two rapid clockwork movements, which has not yet been realised, and which is frequently sought after in electric telegraphy and in other applications. use of perfumes, whether by burning or other- The principle of the method under notice AGRICULTURAL ENGINES. [OTWITHSTANDING our boasted pro NoTres in the substitution of machinery for manual labour in agricultural operations, there cannot be a doubt but that we are not so forward in respect of the machines themselves as we ought to be. Unquestionably we have of late made rapid strides in adopting machine labour in almost every department of agriculture, and great has been the success attending the efforts of engineers in this direction. But whilst we have been working out the end we have neglected to keep the means proportionately advanced. In other words, while enlarging and extending the application of machinery to the purposes of agriculture, we have neglected the source of power-the engine and hence agricultural engines have come to rest their claims for consideration in many cases upon engines, is nevertheless a feature demanding serious is more difficult to devitrify than a glass conpaint and varnish. Paint is to the agricultural consideration in the cases of an agricultural loco-taining a very small proportion, as all common engine what charity is to the human machine motive or portable engine. There are many other glass does. Another point studied was the it covers a multitude of defects. Upon this points of importance to be observed in the produc-influence of increased proportions of sand, and tion of a good engine for the purposes in question, point, however, it is but fair to say that a and as the subject is one of great moment, we trust the author states that a very satisfactory plate decided improvement was manifested by some that it will receive special attention at the hands of glass can be obtained by employing 350 parts makers who exhibited at the last agricultural some competent designers, who will not assume the of sand to 100 parts of sulphate of soda and show, where, as we pointed out at the time, present general arrangement and appearance of 100 parts of chalk. The optical properties of there were one or two instances of departure the fulfilment of a want which has been this glass were examined, and it was found to such engines, as being a type necessarily to be folfrom the old rule of ornamentation and emso much felt. have a very low refractive power. M. Pelouze bellishment. And the plain sober grey laid found that the proportion of sand could not on the bare work is an improvement we hope We fully concur in the views put forth by be usefully increased beyond the above amount. to see increasingly adopted as each succeeding our contemporary, as a light and easily trans- Some experiments with magnesia led to the show comes round. Farmers are not children, to portable agricultural engine is unquestionably conclusion that this body must be carefully be dazzled by gaudy alternations of red, white, a great desideratum, inasmuch as such engines avoided in the manufacture of glass. The and blue, relieved here and there by a noseare in most cases required to be transported author has also devoted a good deal of study gay. Neither are they fools, although they over imperfect and badly kept roads; and to the causes of the alteration of colour which may not be engineers, and they will by exmoreover it has been convincingly proved that glass undergoes when exposed to direct sunperience soon learn to despise mere meretri- the working of boilers by the action of bearings light. It is well known that a window glass cious ornament when they see it contrasted attached to them is the frequent cause of disoriginally of a pale green colour becomes with a plain workmanlike appearance. But astrous calamity. Hence it is clear that in all yellow after some exposure to the sun. This it is not so much to the external appearance cases not only should the construction of the change, M. Pelouze states, results from the reof agricultural engines as to the lack of real boiler itself be such as to ensure the greatest action of the protoxide of iron on the sulphate improvement we find manifested in many of possible immunity from accident, but all the of soda in the glass, by which peroxide of iron their details, that we wish now to call at-strains of the working parts should be carried and sulphide of sodium are produced. When tention. And we have been led to these ob- by independent framing, or at least by framing a glass changed from green to yellow by such servations by noticing some sensible and per-so arranged as that no undue strain may be re-action is exposed to heat, an inverse re-actinent remarks upon the subject which appear thrown upon the boiler. These, we think, are tion takes place, sulphate of soda and protin the present issue of the Civil Engineer and points which cannot be too strongly enforced, oxide of iron are reproduced, and the glass Architect's Journal. Although a publication and it certainly appears to us that, looking at returns to its original colour.' devoted for the most part to other than me- what has been done in the best steam fireThe increased demand for nitric acid which chanical subjects, our contemporary in the engines, there will be little difficulty in arriving has arisen of late years has set manufacturers present instance exhibits considerable discern- at what is desired. Engines which have usually and chemists thinking of cheaper modes of ment upon the point in question. to be entrusted to unskilled and often ignorant production, and Dr. Wagner has revived with farm labourers cannot be too safe in their consome modifications a process employed by the struction, or too free from all chances of acci-old distillers of aqua-fortis. They heated todent likely to escape the most careless observation. The accessibility to all the working parts should be of the most perfect character. Believing as we do that this is a subject really deserving of serious attention on the part of engineers, we heartily join in the hope that it will soon be taken in hand by some competent designers who will give full weight to the various considerations above advanced, rather than take the present type of engine as being one to be implicitly followed. The article is on the recent Smithfield Club Show, and the writer, after analysing the various machines, comes to the conclusion that the best of the engines exhibited were too clumsy, and that their weight ought in most cases to be reduced considerably. The system of attaching the cylinders and fly-wheel bearings to the boilers is considered highly objectionable, and one that cannot be altered too soon. With regard to the boilers, speaking from our own observation and from the practical results attained during some years past in fire and other engines, a well-proportioned boiler on the "Field" system, which is now coming into extensive use for various purposes, would be the best that could be adopted by our agricultural engineers for their portable engines. With such a boiler an engine NOTES ON RECENT SCIENTIFIC DIS- gether nitre and sulphate of iron, and sometimes moist clay, and so obtained the mixture of nitric and hyponitric acid, called aqua-fortis, Wagner states that the hydrated alumina obbauxinite, may be employed for the same purtained in the manufacture of soda from cryolite or pose. When this is heated with Chili saltpetre, (nitrate of soda), nitric and hyponitric acids are evolved and aluminate of soda remains, which treated with carbonic acid yields carbonate of soda, and leaves the alumina for another operation. Thus the manufacturer would start with one stock of alumina, which would always be recovered. Silicate of soda and silica itself will displace the nitric acid from nitrate of soda, the latter at a lower temperature than would ascend and descend hills and steep in- New use for the Diamond-The Manufacture hydrated alumina. In this case, also, a market. of Glass-Manufacture of Nitric Acid-Oxi-able product-silicate of soda-is obtained as dation of Peuter-A Test for Wood in Paper. residue. These processes may perhaps deserve the attention of manufacturers. SUBSTANCE which has hitherto, with A the exception of one practical appli-ticul decomposing nitrate of soda with sulKuhlmann, we believe, has revived the prac cation, ministered only to the vanities of man-phates, using those of magnesia and zinc. kind, seems likely to become an object of much The relative oxidisability of tin and lead in greater utility. A diamond machine for per- an alloy of the two metals has been investiforating rocks has been constructed and is gated by Preyer, who would appear to be actually at work boring a tunnel on the Bour- largely engaged in the manufacture of pewter. bonnais Railway in France. We may say at He states that when a large quantity of this once that diamonds of the first water are not alloy is prepared the product will contain the necessary for this work. The black diamond two metals in proportions which will vary of Borneo is sufficiently hard for the purpose. somewhat with time. In all cases the tin The machine is of very simple construction, oxidises more quickly than the lead, and There is an iron tube terminating with a steel therefore the first products will contain more ring, and into this ring the diamonds are in in proportion of the tin, and the last more of serted at moderately short intervals, a row on the lead. the outer and a row on the inner edge. The Wood is coming into considerable use in tube is made to rotate, and of course pressure the manufacture of paper, and a test for its is kept up against the rock. The hollow of the tube receives the nucleus cut out of the presence may be useful to our readers. Schapringer recommends sulphate of aniline, but rock, which can be knocked off with a ham-Behrend states that ordinary nitric acid is a mer. It is said that the machine actually in more-delicate and certain reagent. Paper conuse bores a very hard rock at the rate of a taining wood is rapidly coloured brown by this metre per hour, although driven only by water acid, especially when the paper is warmed. clines without any material disturbance of the water-level; it is much lighter in weight and more economical in working than the boilers at present employed, besides being free from leakage, and safer as regards explosions of which we hear a great deal too much in this class of engine. Besides this, it is more readily repaired in case of mishap, of which, however, there is less chance than with boilers of the ordinary construction. Mr. Field, the inventor of this boiler, would do well to turn his attention to the subject of portable engines. The steam fire-engines constructed from his design by the Messrs. Merryweather, exhibit an amount of mechanical ingenuity and sound judgment, which, if brought to bear upon the production of an efficient agricultural engine, would result in creating a class of machines that would take a leading stand in the market. Although their respective uses differ widely, there is nevertheless a certain affinity in the requirements of steam fire-engines and agricultural locomotives. In both cases it is desirable to obtain the requisite power within the smallest practicable weight. It is likewise most important, says the writer of power. the article to which we have alluded, that the boil- SOCIETY OF ENGINEERS. AT the last meeting of the above society, hadd on February 4, W. H. Le Feuvre, Esq., president, in the chair, the following paper on Action of Safety-valves for Steam Boilers," &c., "Experimental Researches into the Nature and by Mr. Thomas Baldwin, was read:-It often happens that a safety-valve is weighted to within a few pounds of the maximum pressur that a common open mercurial steam-gange will indicate, and it frequently happens that, when no steam is taken from the boiler, or the boiler has an excess of capacity over the work it has to do, the pressure will rise in spite of the safetyvalve and blow out the mercury of the steamgauge, in which case the safety-valve does not answer the purpose intended, as it allows the steam to rise to a higher pressure than it ought to do. This state of things having come under the author's personal observation, it was deter. mined, in the year 1857, to make experiments to ascertain to what extent the pressure in a steam boiler might exceed the calculated pressure on the safety-valve without the safety-valve being sufficient to carry off the steam generated in the boiler. For this purpose a small valve lin. in diameter, having a lever and weight, and of the ordinary construction, was fixed on the top of a lin. pipe 12in. long inserted in the manhole cover of a common two-flued Lancashire boiler, belonging to Mr. Daniel Smith, of Bury, Lancashire. The lever of the valve was 14in. long, and the distance from the centre of the valve to the fulcrum was 2in., the movable weight being 6'091b., and the weight of the lever and valve was we find, although the pressure on the valve has taken and allowed for in all the experiments. The pressure in the boiler was 671b., and the The curve line a b (fig. A) shows the height 70 a 60 55 50 E Ъ a lin. diameter at the base, and lin. high from base to apex. The valve was found at the close of the experiment to have lost all the cement, which will account for the irregular shape of the curve. The pressure in the boiler was 65lb. per square inch, and the valve opened 1.20in. when the weight upon it was reduced to 54ib, on the square inch. Fig. L shows a diagram con. structed from an experiment made with an ordinary valve with three wings and conical face, the angle of the slant side being 45 deg. and breadth of face in., the diameter of the inside of the valve as before. The pressure in the boiler for this experiment was 671b., and the valve lifted 1-20in. when the pressure on the valve was re duced to 51 lb. per square inch. Fig. M is constructed from an experiment made with the same valve as used for figs. E, F, G, and J, with this difference, that the face of the valve was 1in. diameter, and the outer portion of the disc very nearly touched the flat portion of the seating-it was not more than 1.100in, from touching. The pressure in the boiler was 671b. per square inch, and the valve only lifted 1-80in. when the weight upon it was reduced to 45lb. per square inch. This experi. ment shows that broad faces for valves ought the valve to open 1.80in. when the pressure in the valve to 45lb. per square inch only allows not to be used; for a reduction of the weight on the boiler is 221b. per square inch above the weight per square inch on the valve. Collecting the results of these experiments, we have the following table : atmo TABLE 1. when the pressure upon it is reduced to 50lb. per a 710 67 615 6.0 including the sphere. 65 57 531 511 73 58 54 523 534 49 59 484 67 67 45 ... 471 ... the valve lifted from its seat as the weight in pounds per square inch was taken off the valve. The vertical lines divide the figures into pounds be seen on boilers blowing very faintly when the Many valves, from 2in. to 5in. diameter may per square inch, and the vertical scale is oneseventh of the horizontal one. The distance the pressure in the boiler is from 15lb. to 201b. per valve opens is exhibited by the distance, measured square inch above the weight per square inch on vertically, from the straight line ac to the curved the valve. This is the case more especially when line a b. At a the valve is closed, and the presthe valve is a disc, and the facing similar to that sure in the boiler is 65lb. per square inch, including the atmosphere. of experiment M. We see from experiment M, The dotted line passing as an extreme case, that if the pressure in a across the figure shows the position of the valve boiler be 45lb. on the square inch, the pressure when lifted one-twentieth of an inch, which would rise with a valve of that construction to would take place when the weight on the valve 671b. before the valve could lift 1-80th of an is equal to about 53 2-3lb. per square inch. The inch, or cause the valve to open 1-20th of its area pressure in the boiler began to increase at d, of aperture. These experiments prove that we which is the cause of the curve of contrary cannot have the common safety-valve of sufficient flexure at that point. The valve used in the exarea to allow the steam, when the furnace is in periment connected with fig. A was a disc of 1in. diameter, guided by pins on the outside. riment made with the same valve as that used for full action, as rapid an exit as it ought to have, unless the valves be very large. It is importFig B shows a diagram constructed from another figs. C and D, with three wings, the disc being reaut that we know what size of an aperture will experiment with the same valve, and at the duced from 14in. to 1 1-8in. diameter. The pres-be just sufficient to take away all the steam that same pressure as before; but in this case the sure in the boiler was 65lb. per square inch. The can be generated in a boiler, so that the pressure pressure did not vary in the boiler during the ex-valve lifted 1-20in. when the pressure on it was shall not rise above a given amount, and since periment. The curve a b is an hyperbola with reduced to 51lb. per square inch. this depends on the quantity of fuel consumed one asymptote very close to the line a C, Fig. 1 shows another experiment with the same and the other at about 48 deg. from the line valve, and at the same pressure of 65lb. in the and the quantity of water evaporated in a given of pressure a c. The valve is open 1-20in., boiler. The valve lifted 1.20in. when the weight Let f the area of the firegrate in square feet. at about 531lb. on the diagram; or, in other upon it was reduced to 524lb. per square inch. pounds of coal consumed on each words, the weight on the valve was 53 lb. when The curves in the last two experiments difer square foot of firegrate per hour, steam in the boiler at 65lb. did not lift the valve from each other, which is probably caused by the more than 1-20in. from its seat, the steam from flow of steam to other places, the boiler being the boiler issuing into the atmosphere. Fig. C used for driving a steam-engine and for boiling shows an experiment with a disc valve 1țin. dia. purposes at the time of this experiment. Fig. Jis meter, with three thin wings passing into the in- another experiment with the same valve as used terior of the valve-seat to guide the valve, the in the experiments E, F, G, but carried to a furpressure in the boiler being 73lb. Although we ther extent in opening the valve. The valve have a pressure of 73lb. in the boiler, the valve opens 1.20in. when the pressure on the valve is does not lift 1-20in. until the weight upon it is reduced to 481b., the pressure in the boiler being reduced to 54lb. per square inch. This is pro- 65lb. per square inch. Fig. K was constructed bably owing to the exit of the steam being re- from an experiment with the same valve as used tarded by the wings of the valve, reducing the for H and I, with this difference, that the spaces area of the passage into the atmosphere. By between the wings were filled up with Roman weighting the valve to 521lb. per square inch, cement until the filling in formed a parabolide |