side with chisels and gouges, taking care to leave the groundwork thick enough to finish up. After the blocking out is completed, begin with the top of the profession in making the head, by leaving a space for the hair a little raised and then engraving the features, taking great pains not to do too much at a cut, for if once spoiled there is no remedy. The neck and breast are done next, as cautiously as the face. The hair is done last, and is the most difficult part to perform, although the uninitiated would think it the simplest, but it is the most difficult work of all, for no matter how good the rest of the work may be, if the hair is poorly executed the whole figure looks bad. In cutting the hair it must be gracefully curled with delicate curves. Sculptured heads are the best models for the learner to study. After the figure or design is finished with the graver, the cameo is polished with pumice stone as smooth as possible, until all the marks of the graver disappear. It is then finished with a stiff toothbrush and potter's clay, or whiting and water, and afterwards washed in pure water, when it will be observed to have that beautiful polish for which cameos are so justly admired and which has made them, on account of their chasteness of colouring, a very popular branch of jewellery. To take the cameo off the stick after it is finished it is necessary to heat the stick over a spirit lamp until the cement warms, when it is ready for framing. It may be observed that the grace of a figure depends much on the drapery.Building News when they reach the point where limestone and ironstone act on each other, and combine to produce slag. The first effect due to the hot gases produced by combustion passing through the furnace will be, to raise through which it passes, up to that point where the temperature of the material limestone is decomposed into carbonic acid and quicklime, (and when the evolution of gases commences, it is likely that the temperature will not increase as quickly as before this point is reached, owing to the liberated gases removing a portion of the heat of the furnace with them); at this point, too, any volatile or organic matter left in the stone by imperfect calcination will be driven off. It is probable, too, that near this place the peroxide of iron in the iron ore is sufficiently heated for the carbonic oxide to act upon it and reduce it to the metallic state, and this action will continue until at last all the iron will be distributed through the stone in the me. tallic form. The intensely heated material now travels on, the intensity of heat increasing as it approaches the "hearth," until at last the "melting region" is reached, where the earthy matter in the ironstone melts, and, acting on the lime. stone, the production of slag follows; a little below this the reduced iron will also melt, and at the same time probably combine with a portion of the carbon of the coke; nearer to the tuyeres still, some or all of this combined carbon may be resolved into the "graphitic" form, traces of silica, lime, &c., reduced and alloyed with the iron, and cast iron result. We will now in like mauner attempt to follow THE THEORY AND WORKING OF BLAST the blast in at the tuyeres, and to explain the PERHA FURNACES. BY WILLIAM CROSSLEY, F.C.S.* ERHAPS no part of "furnace chemistry" is so little understood as that connected with the manufacture of iron in a blast furnace, and yet experience and frequent experiment have gradually improved the appliances and construction of blast furnaces, and shown the conditions under which they work most favourably, until at the present time I do not know of any other manufacture that is carried out on such a sys. tematic and gigantic scale, nor one which promises at no distant period to be more thoroughly understood. Of course, in some of the older districts, and especially with those firms who have long had a name for the quality of the pig or "merchant" iron they produce, and a demand which places them above competition, the appliances and the process of manufacture are very primitive; but in the modern districts, and especially in Cleveland, every advantage is taken of all the discoveries and appliances that seem at all likely to answer the purpose for which they are intended; and the enterprising spirit shown by the ironmaster in the erection of improved plants and the alteration of old plants, to decrease the cost, improve the quality, and increase the make of iron, is worthy of all com mendation. I purpose in the present communication to point out some of the improvements that have been made, give some explanation of their effect, and, if possible, show in what direction any further efforts we may make ought to tend. In a blast furnace the fuel and the material on which it has to act when undergoing the process of combustion are introduced together at the top of the furnace, and it takes from twenty-four in some of the older furnaces, to forty-four or even fifty hours in those most recently built, before it reaches the "crucible" part or the hearth, where combustion is going on, the cast iron formed and melted, and the slag allowed to escape. To assist ourselves in fully understanding the subject, it will perhaps be the best plan to follow the material in the changes it undergoes from its introduction at the top to its elimination as slag and iron at the bottom. In an ordinary-sized furnace the material will be introduced about 40ft. from the point of combustion or the tuyerest, and hence it will be very gradually raised from the temperature at which it comes from the calcining kilns, to the highest temperature of the furnace, and it is probable that the largest pieces of ironstone or limestone will be of nearly the same uniform temperature * Communicated to the Chemical News by the author. + In some of the larger furnaces the material is intro duced 70ft. from the tuyeres, and in two furnaces recently built by Messrs. Bolckow and Vaughan, at Eston, the height of the furnaces has been increased to 96ft. .27.00 per cent. And on the assumption that the whole of the oxygen in the iron ore oxidised its equivalent of carbonic oxide to carbonic acid, and that this carbonic acid is not again reduced, we should have a gas containing the carbonic acid and carbonic oxide in the following proportions: Carbonic acid Carbonic oxide Carbonic acid Carbonic oxide 33.72 66.58 32.75 67.25 changes it takes part in before finally leaving the The nearness of the above figures to each other would certainly seem to bear out the theory I have advanced; and I may here state that from some original investigations, as well as from the analysis of the gas escaping from Ormesby furnaces, I have bad the above results confirmed. 15 per cent. has been deducted from the charcoal, for ash, volatile matter, and moisture. I should here state that in the above calculation It is hoped that ultimately the analysis of furnace gas may lead to a better knowledge of the changes which take place in a blast furnace, in the reduction and smelting of cast iron; but those already published are extremely unsatisfactory in some respects, either from the bad choice of furnace from which the gas analysed has been collected, or from the fact that there have been so many interfering circumstances at the time, that it is difficult to draw any reliable conclusions from the results obtained. I have devoted a great deal of time to the examination of the analysis made by Ebelmen at Clerval and Audincourt in France, and at Seraing in Belgium; by Bunsen and Playfair at the Alfreton furnaces, England; by Bunsen, at Veckerhagen; and lastly, by Scheerer and Lanberg at Baerum, in Norway. I found it impossible, from the reasons named, to gain any information of value, with perhaps one exception-viz., in the case of the analysis of gas from a furnace at Clerval, in France, by Ebelmen, a French chemist, which analysis seems to point to the fact that there is not that constant series of changes from carbonic oxide to carbonic acid, and from carbonic acid to the oxide, which has always been supposed to be the case, but that all the carbonic acid produced by the oxygen of the iron ore combining with the carbonic oxide leaves the furnace as carbonic acid, and is not again reduced to carbonic oxide-in other words, that the temperature at which oxide of iron can be reduced by carbonic oxide is below that at which carbon can remove an equivalent of oxygen from carbonic acid. Ebelmen gives the following as the result of his analysis of the gases escaping from a furnace at Clerval in France: The above results, then, seem to indicate (excuse me for stating it so frequently) that the reduction of iron takes place in a much higher and cooler part of the furnace than is generally supposed; and that the change of carbonic oxide into carbonic acid, and its subsequent reduction into carbonic oxide again, does not take place; carbonic acid once formed in the reducing region is never again converted into carbonic oxide, but leaves the furnace as carbonic acid. If the above views are correct, they also explain another process adopted in the manufacture of iron which has always been enveloped in some amount of mystery-viz., the theory of the calcination of ironstone. There cannot be the slightest doubt that the beneficial results obtained by the calcination of ironstone are greater than would be obtained by a mere decrease in weight and the previous evolution of volatile matter by exposure to intense heat; for in calcining, besides a loss of about 20 per cent. which the ironstone suffers, the protoxide of iron absorbs oxygen and becomes converted into a higher oxide, called the peroxide-that is, every thirty-six parts of oxide of iron, containing eight parts of oxygen, absorb four more and the oxygen thus absorbed. as well as that, originally contained in the ore, by oxidising their equivalent of carbonic oxide, thus assist in heating and preparing the material for the further changes it has to undergo in the lower part of the furnace. parts, If the above is not the case, I would ask how it can be explained that the calcination of limestone does not give equally beneficial results with those obtained from the calcination of ironstone, when by this operation limestone loses about 42 per cent. of its weight, where ironstone only loses about 20 per cent. Taking these facts into consideration, then, I think we are justified in stating that calcination is productive of good, as much from the fact that it gives oxygen to the iron as from its effect in driving off the volatile matter. (To be continued.) Great quantities of coal have lately been dis. covered in the Val d'Oocia, in Sienna. lever is carried by the arm u past its centre, it falls by its own weight into the opposite position to that it before occupied, and in so falling it moves the clutch box c and thereby reverses the motion. By removing any one of the set serews which fastens the V pulleys k no further motion will be given to the particular pulley, as its worm-wheel or other gearing would then run idle; this pulley may then be repaired without stopping the others, and a handle may be fitted to the square end of its shaft to allow of the scraper or scrapers connected therewith being worked by hand. When the clutch box c is getting just into gear and reversing, the weight is thrown off it by means of the slots n allowing the worm-wheels i to travel a certain distance without driving the V pulleys k and chains l. APPARATUS FOR CLEANSING BOILER m passed through a slot n in the pulley. The M has R. EDWARD GREEN, an engineer, of provements in gearing or apparatus for driving scrapers employed in cleansing the flues and tubes of boilers and heating apparatus." His invention relates chiefly to the scrapers used in what are known as "fuel economisers" for keeping the surface of the pipes of the economisers clean and free from soot and other deposit. These scrapers are ordinarily worked by chains passed over pulleys formed with a V groove. Mr. Green's invention consists first, in the employment of one reversing motion for several pulleys round which the scraper chains pass, such pulleys being driven by worms or other gearing; secondly, in obtaining a reciprocating motion by means of a positive motion chains 7 thus receive motion for working the scrapers, but in order to convert this positive motion of the chains into a reciprocating motion, the worm wheels i, by preference that next the bevil wheel f, is made to gear as shown into a pinion o on a worm shaft p, the worm q of which drives an idle worm wheel r, and this in its turn gears into and drives another wheel s working on a stud t; on this stud or centre is placed a pair of arms u u, the position of which is adjustable by means of a set screw and slot hole v to allow these arms u u to be set to any position with the object of altering the length of traverse of the chains 1. As these arms u u move round, one of them at the proper time comes against a knock-over lever w, which is pivoted at its lower end, while its upper end is by preference weighted; when this THE SAFETY FISHING BOAT OF THE ROYAL NATIONAL LIFEBOAT INSTITUTION. I through the foundering of fishing-boats on the N consequence of the frequent loss of life coasts of the United Kingdom, it appeared to the Committee of the National Lifeboat Institution that the safety of the larger class of open and half-decked fishing-boats on our coasts might be greatly increased by enabling them to be made temporarily insubmergible, in the event of their being overtaken by gales of wind when at long distances from the land. No doubt was entertained by practical persons on the coast, who were consulted on the subject, of the need of such improvements and of the feasibility of the plan proposed to effect it; but the coast boatmen being an inert class, not readily departing from what they have been accustomed to, it was not thought likely that they would themselves initiate any such changes, however needed. The committee, therefore, decided to build a few pattern boats, and to place them at some of the principal fishing stations, in the hands of experienced and trustworthy boatmen, to whom they would be lent, or let at a small percentage on their earnings for a period of twelve months; at the end of which time they might be sold, and would remain in the several localities where placed as samples, from which the other local boats might be improved in a similar manner. As these boats would be seen by large numbers of fishermen from different places at their chief ports of rendezvous during the fishing seasons, it was considered that it might not be necessary to build any large number in order to make them generally known, and that a short period would suffice for those to whom they were entrusted to form a correct estimate of their properties. In the event of the experiment proving successful it was believed that a great boon would thus be conferred on the fishermen and other boatmen of certain classes on the coast, as not only would numberless lives and boats be saved that in course of time would otherwise be lost, but that the boats would often be able to remain at sea and safely continue their fishing in threatening weather, instead of returning to the shore at great pecuniary loss to their crews, as is now too frequently the case. Five of such boats were accordingly orderedthree to be built in Scotland, one at Yarmouth, and one by the builders to the Institution in London. Two of the boats built in Scotland, one at Peterhead, and the other at Anstruther, have been tested and are now at work, having already afforded the utmost satisfaction to their crews, as will be seen from the following extracts of letters received at the Institution. Captain A. Sim, honorary secretary of the Lossiemouth branch of the Institution, writing from that place on March 18, states:-"The safety fishing-boat inst., at six a.m., and was here the following day at five p.m., after lying to for some time off Peterhead, thus making the voyage in thirty-six hours-Do bad test of her sailing qualities. She has been very much admired here by all fishermen; in fact the seafaring population are unanimous in their opinion, that she is just the thing for this coast, and I trust she may be the beginning of a new era in decked boats." William Boyd, Esq., honorary secretary of the Peterhead branch, also writes on the same date :-" You will be glad to hear that the new safety fishing-boat gives very great satisfaction. John Geddes, the lifeboat coxswain, lay alongside the Lossiemouth boat in the Firth of Forth, and declares that she is a fast THE SAFETY FISHING-BOAT OF THE ROYAL NATIONAL LIFE-BOAT INSTITUTION. FIG. 1. FIG. 3. FIG. 4. Fie. 5. FIG. 6. LIGHT OSTOVED D FIG. 7. PUMP SCUTTLE Railer, having accomplished the run from here in thirteen hours. She works well and satisfactorily, but she has not experienced such bad weather as would thoroughly try her safety powers." common coasting barge with her hatches on and covered over will convey an exact idea of the simple manner in which the above arrangements are carried out. The size of these boats, viz, length 40ft., width 14ft., depth amidships 7ft., has been selected as the most convenient size, for use both in line and net fishing. A sixth boat, however, 45ft. long by 15ft. wide, is about to be built for Anstruther, where the fishing boats go as far as 100 miles from the land to fish, and have lines on board of the total length of 23,500 yards, or nearly 134 miles, which require a large space to stow them away, all coiled in baskets, besides a cargo of fish. The figures in the accompanying engraving show the general form, the nature of the fittings, air compartments, shifting-coamings, and and hatches of one of the safety boats, 40ft. in length and 14ft. in breadth. In figs. 1 and 2, the elevation and deck plans and the general exterior form of the boat are shown, with the sheer of gunwale, length of keel, and rake of stem and sternpost. The dotted lines of fig. 1 show the position of the compartments, bulkheads, masts, pumps, thwarts, and shifting flat The committee of the National Lifeboat Instior deck; a scuttle in boat's side above the side tution entertain sanguine hopes that this experidecks; b scupper in the boat's side above the ment will be ultimately productive of much stern deck; c screw plug, to drain the stern benefit, both by saving life and property. In compartment. In fig. 2, A represents the open conclusion, it may be stated that the National hatchways of the main hold, to be covered with Lifeboat Institution has been engaged during the portable hatches and a watertight tarpaulin cover last two or three years in perfecting this model in gales of wind; B shifting coamings for the of the safety fishing boat. Captain J. R. Ward, hatches; C the side deck; D the forecastle deck; B.N., its Inspector of Lifeboats, has visited and E the stern deck. Fig. 3 represents a sec- during that period some of the principal fishing tion at the after air compartment, showing the stations on the coast of the United Kingdom, thwart, and crutch to receive the mast, and the with the view of eliciting from the most exstern deck. In fig. 4 the exterior form of trans-perienced fishermen practical suggestions, to be verse sections, at different distances from stem to stern, is shown. Fig. 5 represents a section at the fore air compartment, showing the thwart and mast. In fig. 6 the shifting coamings over the main bold are shown, with the portable batches H in place, and I the shifting deck or flat. Fig. 7 represents a midship transverse section; F the thwart, C the side deck, B the shifting coaming over the forehold, I the shifting deck or flat, and H the hatches in place. Fig. 8 represents a section abaft the foremost bulkhead, showing the shifting coaming B and portable incorporated in the construction of the boat, so that thus she may be correctly termed an omnium gatherum safety fishing boat. It may also be mentioned that the drawings of the boat have been furnished by Mr. Joseph Prowse, of her Majesty's Dockyard, Woolwich, who, with the kind permission of the Admiralty, superin. tends the building of all the lifeboats of the Institution. hatches H in place, and I the shifting deck A or flat. NOTES ON PHOTOGRAPHY. Ta meeting of the photographical section of the Literary and Philosophical Society, The interior fittings of the boats have been so held January 10 last, Dr. J. P. Joule, F.R.S., arranged as not to interfere with their everyday Vice-President of the Section, in the chair, Mr. work, yet so as to enable them to be quickly Coote exhibited a selection from the series of made insubmergible. This object has been photographs by Braun, of Paris, consisting of effected, as is clearly shown in the engravings, copies of drawings by the old masters, from the first, by making the usual fore cabin a watertight originals in the Louvre. Mr. Coote explained apartment, the access to it being by a watertight the method by which they were supposed hatch in the deck, instead of an open door at the to be printed, and from the appearance of side; second, by making the usual compartment some of the prints there could be no doubt that at the stern also watertight; third, by running a side deck along either side, as in barges and in some of the smaller class of yachts, called well boats, thus leaving a large open main hatchway, of sufficient size for conveniently working the nets, yet which, by the aid of coamings and hatches and a watertight tarpaulin stowed away in the hold or fore cabin in fine weather, could in a few minutes, on the occurrence of bad weather, be securely covered over so that no water could get access to the hold on a heavy sea breaking over the boat. The inspection of a one of the processes suggested by Sir John Herschel about the year 1840, or some modification, had been employed; and it was evident that the method proposed by Mr. Gatty would also produce similar results. The prints are remarkable for their perfect resemblance to old draw ings and sketches, and, as studies for artists and for use in schools of design, are quite equal to the originals. Of their permanence there cannot be the least doubt. The following communication from Mr. J. B. Dancer, F.R.A.Š., was read:-At a meeting of the Photographical Section, October 4, 1866, it may b remembered that I exhibited some specimens o photographs in various colours, on paper and calico, a process invented by Mr. John Mercer, F.R.S. I did not recollect sufficient of what Mr. Mercer had told me of the process to give you any definite information as to the production of the colours. A few days since I stumbled on his description. Mr. Mercer read a Paper on the subject at the meeting of the British Association at Leeds, in the year 1858. He exhibited coloured photographs on paper and calico, and gave the following directions for producing them. Direc. tions:-34oz. of sulphate of iron are converted into peroxalate; this is diluted to 2 gallons, and will impregnate 200 square yards of paper. The paper being floated on the solution until fully wet in the usual way, it is then exposed, and afterwards steeped in some solution which only acts on that part where the iron has been reduced from the per- to the protoxide. Red prussiate of potash and sulphuric acid act well, making the image blue and the ground white. Sulphocyanide of potassium and a salt of copper form another bath; the protoxide of the picture deoxidises the copper, and the sulphocyanide of the suboxide of copper is fixed in the cambric or paper. This may be converted into the red prussiate of copper. A vast number of colours may be obtained by replacing the iron or copper by other metals, such as lead, zinc, tin, mercury, silver, gold, or manganese. With these bases may be used various dyes, as madder, cochineal, murexide, logwood, galls, or quercitron bark, besides the iodides, chromates, prussiates, or oxides of the metals themselves and mixtures of these. He also showed how the peroxalate paper might be used as a fair actinometer, by placing a slip between the leaves of a book and pulling it out by steps every stated number of seconds. It is then easily converted into a graduated scale. At a subsequent meeting of the same section, Samuel Cottam, Esq., in the chair, Mr. Wardley said that he had observed recently in the Photographic journals that complaints were made as to the appearance of streaks on collodion plates in the direction of the dip. He had never until lately seen anything of the kind, but he had been using some collodion which produced the markings, and he noticed that the streaks could be seen on the plates when taken out of the bath, and before exposure. The marks were not such as would be removed by re-dipping the plate and moving it from side to side in the solution; and he thought the cause would be found to arise from the collodion being over oxidised. He had used collodion containing about one-eighth less iodizing solution, and found that the streaks had disappeared. Mr. Brothers, F.R.A.S., exhibited a number of photographs taken during the eclipse of the sun on the 6th ult. He said that he had antici pated some difficulty in photographing the sun from the excess of light causing over exposure, as the image was taken at the focus of the tele. scope without enlargement throngh an eyepiece. To overcome that difficulty the aperture of the telescope was reduced first to two inches, and then to half an inch; and collodion and developing solution which had been mixed upwards of twelve months, and an old silver bath were used. The exposure was as instantaneous as could be made by hand. In explanation of the four prints being on one plate, Mr. Brothers stated that the slide he used for astronomical photograpy is arranged so that four negatives of the sun or moon can be taken on the same plate, an advantage which he had found of much importance in this kind of work. The time occupied in taking the four negatives on plate No. 3 was thirty seconds; No. 4 twenty-five seconds; and the last set was taken in twenty seconds-an average of five seconds for exposing and changing the position of the plate. Two of the prints, 3 and 4 of the series, were mounted, in reversed order, for the stereoscope, and they exhibit very good stereoscopic effects although taken from the same station, the difference in the position of the moon in an interval of about seven minutes being sufficient for the purpose. The negatives on No. 3 were taken at 9 hours 32 min. to 9 hours 32 min. 30 sec., and those on No. 4 at 9 hours 39 min. to 9 hours 39 min. 25 sec. Mr. Brothers also exhibited a photograph on canvas printed without the aid of bitumen of Judea or gelatine, or of any other substance likely to change by time. The print is so completely stained into the canvas as prepared in the ordinary way for artists, that it cannot chip or rub off. Another advantage is that hyposulphite of soda is not required to fix the image. ENAMEL ENAMELLING IRON. a flat iron plate to cool, and thus they have NAMELLING iron is almost a new art. No metal is capable of receiving a coating of vitrified porcelain or enamel unless it is capable of withstanding a red heat in a furnace. Articles of cast iron, as a preparation for enamelling, are first heated to a low red heat in a furnace, with sand placed between them, and they are kept at this temperature for half an hour, after which they must be allowed to cool very slowly, so as to anneal them. They are then subjected to a scouring operation with sand in warm dilute sulphuric or muriatic acid, then washed and dried, THE BORAX LAKE OF CALIFORNIA. when they are ready for the first coat of enamel. E have occasionally referred to the Borax This is made with 6 parts by weight of flint glass broken in small pieces, 3 parts of borax, 1 ticulars thereof, which we take from the San of red lead, and of 1 the oxide of tin. These Francisco Mercantile Gazette:-The source of substances are first reduced to powder in a supply of Borax is a large and shallow basin, mortar, then subjected to a deep red heat for called Borax Lake, near Clear Lake, in Napa four hours, in a crucible placed in a furnace, Co., California. The owners of this property, during which period they are frequently stirred, to desiring an authentic statement of its value and mix them thoroughly; then toward the end of the resources, have availed themselves of the serheating operation the temperature is raised, so as vices of Mr. J. Arthur Phillips, of London, who to fuse them partially, when they are removed in consented, in the midst of pressing engagements a pasty condition and plunged into cold water. during his recent short sojourn in California, to The sudden cooling renders the mixture very visit Borax Lake, and report his opinion of it. brittle and easily reduced to powder, in which The following is a synopsis of the descriptive condition it is called frit. One part of this frit portions of his report:-The sheet of water by weight is mixed with two parts of calcined from which the supply of borax is obtained is bone dust, and ground together with water until separated from Clear Lake by a range of hills it becomes so comminuted that no grit will be belonging to the cretaceous period, and has, sensible to the touch when rubbed between the under ordinary circumstances, a length of about thumb and finger. It is then strained through a mile, with an average width of half a mile; a fine cloth, and should be about the con- but its extent varies somewhat at different sistency of cream. A suitable quantity of this periods of the year, since its waters cover a semi-liquid is then poured with a spoon over the larger area in spring than during the autumnal iron article, which should be warmed to be ena- months. No stream of any kind flows into this melled, or, if there is a sufficient quantity, the iron basin, which derives its supply of water from the may be dipped into it and slightly stirred, to re-drainage of the surrounding hills, as well as, in move all air bubbles and permit the composition to adhere smoothly to the entire surface. The iron article thus treated is then allowed to stand until its coating is so dry that it will not drip off, when it is placed in a suitable oven, to be heated to 180 deg. Fah., where it is kept until all the moisture is driven off. This is the first coat; it must be carefully put on, and no bare spots must be left on it. When perfectly dry the articles so coated are placed on a tray separate from one another, and when the muffle in the furnace is raised to a red heat they are placed within it and subjected to a vitrifying temperature. The furnace used is similar to that used for baking porcelain. This furnace is open for inspection, and when the enamel coat is partially fused the articles are withdrawn and laid down upon before alluded to, over a pound in weight. The largest crystals are generally enclosed in a stiff blue clay, at a depth of between 3ft. and 4ft., and a short distance above them is a nearly pure stratum of smaller ones, some 2 in. or 3in. in thickness, in addition to which crystals of various sizes are disseminated throughout the muddy deposit of which the bottom consists. Besides the borax thus existing in a crystallised form, the mud is itself highly charged with that salt, and, according to analysis of Professor Oxland, when dried affords in the portions of the lake now worked (including the enclosed crystals) 17·73 per cent. Another analysis of an average sample, by Mr. Moore, of San Francisco, yielded 18.86 per cent. of crystallised borax. In addition to this, the deposit at the bottom of the other portions of the basin, although less productive, still contains a large amount of borax. It has been further ascertained, by making pits on the lake shore, that clay, containing a certain proportion of borax, exists in the low ground at a consider. able distance from the water's edge. The borax at present manufactured is excla. sively manufactured from the native crystals of crude salt, whilst the mud in which they are found is returned to the lake after the mechanical separation of the crystals by washing. The extraction of the mud is effected by the aid of sheet. iron cofferdams and a small dredging-machine. Until recently, the only apparatus employed consisted of a raft, covered by a shingled roof, which has an aperture in its centre about 15ft. square, and above which are hung, by suitable tackle, four iron cofferdams, 6ft. by 6ft. and 9ft. in depth. This raft or barge is moored in parallel lines across the surface of the lake, and at each station the four dams are sunk simultaneously by their own weight in the mud forming the bottom. When they have thus become well embedded the water is baled out and the mud removed in buckets to large rectangular washing vats, into which a continuous stream of water is introduced from the lake by means of Chinese pumps-the contents of the cisterns being at the same time constantly agitated by means of rakes. In this way the turbid water continually flows off, and a certain amount of borax is finally collected in the bottom of each tank, which is subsequently recrystallised; but from the density acquired by the washing water, of which no less than 70,000 gallons are daily employed, it is evident that less than one-half of the borax existing in the form of crystals is thus obtained, whilst that which is present in the mud itselfis again returned to the lake. The dredging-machine recently introduced is a decided improvement on the cofferdams, and may, trilling tions, be made a very efficient machine; but the mud brought up by it is subjected to the washing process before described, and a small proportion only of the borax is obtained for re-crystallisation. The crystals of crude borax thus daily obtained now amount to about 3,000lb., and after being carefully washed they are dissolved in boil. ing water, and re-crystallised in large lead-lined vessels, from which the purified borax is removed into boxes, containing 1121b. each, for the purpose of being forwarded to San Francisco. The product of refined borax now daily obtained ap pears to vary from 2,500lb. to 2,800lb., which is prepared and packed for market. It is evident from the foregoing description that the present system of working is by no means calculated to develope the best results which this property is capable of affording, and that in order to do so it will be necessary to adopt some method for the lixiviation of the mud. The total extent of this muddy deposit considerably exceeds 300 acres, and if we assume that of this area only 100 acres, or that portion now worked for borax crystals, is alone sufficiently rich to pay the exall probability, from subterranean springs dis- penses of treatment, we shall arrive at the follow. charging themselves into the bottom of the lake. ing figures:-One hundred acres are equivalent In ordinary seasons the depth thus varies from to 484,000 square yards, and if the mud be worked 5ft. in the month of April to 2ft. at the end of to the depth of only 3ft., this represents 565,000 October. The borax occurs in the form of cubic yards; or, allowing a cubic yard to weigh crystals, of various dimensions, embedded in the a ton of 2,240lb., which is a very low estimate, mud of the bottom, which is found to be most the total weight of 100 acres of mud in its wet productive to a depth of about 3 ft., although a state will be 565,000 tons. If we now assume bore-hole, which was sunk near the centre to a that the mud extracted from the lake contains 60 depth of 60ft., is said to have afforded a propor- per cent. of water, this will correspond to 226,000 tion of that salt throughout its whole extent. tons of dry mud, containing, according to the The crystals thus occurring are most abundant mean of the analyses of Professor Oxland and Mr. near the centre of the lake, and extend over an Moore, 18:29 per cent. of borax ; but if in practice area equivalent to about one-third of its surface; only 12 per cent. of borax be obtained, this will but they are also met with, in smaller quantities, represent 27,120 tons of crystallised salt. A carein the muddy deposit of the other portions of the ful consideration of the phenomena attending the basin-some of them being, in the richest part production of borax leads to the belief that its formation is continually going on, by the decomposition of carbonate of soda by boracic acid emitted from sources beneath its bed. Should this be the case it is probable that any moderate extraction of borax may be replaced by the form. ation constantly taking place. THE MONT CENIS TUNNEL. THE Savoie. Tr fonewing particulars concerning the Mont Cenis, are gleaned from the Journal de The excavations had been for the last two years delayed on the French slope by a vein of quartz, which did not admit of an advance of more than from 2ft. to 21ft. a day. That layer has now been got through; and one of much softer stone having succeeded, the perforating machines are able to accomplish double that distance each day. In a short time, when certain improvements shall have been effected in the machinery, from 6ft. to 7ft. will be perforated every twenty-four hours. After the section now worked, a portion of schist, equally friable, will be entered on, and this has already been reached The united progress will then amount to a total of 13ft. per diem, and in four years the tunnel will be completed. In the meantime, the English company of Mr. Fell is actively pursuing for the State the restoration of the Imperial road between St. Michael and Modane, which was carried off on several points, as may be remembered, by an inundation of the Arc in Autumn last. More than 1,500 men are employed on that work. The same firm is also proceeding with the railway over Mont Cenis, which it hopes to be able to open for traffic before the end of the present year. on the Italian side. Obituary. PENETRATION OF CHILLED SHOT. you term "utterly irreconcilable." These dif. full effect of velocity or charge. Cheltenham, March 29. BERTRAM MITFORD. [We do not see any analogy between the case in question and the horse or the candle. The initial velocity of a projectile is at its maximum immediately upon its exit from the muzzle of the gun. If the future velocity were in an increasing ratio, as the resistance of the air is constant (15lb. per square inch), the range of the projectile would be limited only by the effect of gravity. Would our correspondent rather stand up before a pistol bullet, truly aimed, at ten paces or at thirty paces? We know which we should prefer.-ED. M. M.] ASCENT AND DESCENT OF MINES. Nabal, Military, and Gunnery Items. The French Emperor has commissioned several naval officers and hydrographers to proceed to various points of the globe in order to determine a certain number of fundamental meridians, which will serve to fix the geographical position of intermediate places. The Gazette du Midi publishesa communication from Toulon, announcing that the French squad. ron is about to have its artillery completely changed. Sixty enormous breech-loaders, on improved carriages, are now ready, and are to be substituted for the guns at present in use. Great progress is being made with the additiona 1 infantry quarters at the Sheet-street Barracks, Windsor. An extensive range of brick buildings, capable of accommodating upwards of thirty married soldiers, has been erected on the north side of The new quarters are well con. the old barracks. trived, there being two upper stories, which are reached by means of staircases, and protected from A spacious block of the weather by verandahs. buildings, designed to accommodate the staff sergeants, has also been erected at the back of the houses on the south side of Victoria-street, and operations are in progress for the construction of other buildings. The 48 hours' cruise which has just been made by the "Royal Alfred" in the Channel, appears to have been attended with very satisfactory results, except on one point. The ship proved wonderfully manageable under sail as well as steam, and the gun-carriages and slides of the 12-ton guns gave no signs of weakness with the guns firing, singly and in broadsides, 40lb. powder charges, with shot. The exception, as reported in the Times, lies in the damage caused by the tremendous concussion from the explosion of such charges. A large hole had been made in the bottom of the lifeboat, and all light wood about the ship's bulwarks or deck fittings had suffered more or less. The following are the results of the trials of various American breech-loading rifles as reported by the military commissioner appointed to examine them. The Roberts breech-loader fired 84 balls WE have to record the death of Captain John conveying the miners up and down the shaft. in six minutes, an average of 14 in one minute, all Norton, which occurred last month at Bray, in Ireland. Captain Norton was, for many years, a contributor to the MECHANICS' MAGAZINE on matters of gunnery, &c. He invented many improvements in rifles and projectiles. We believe him to have been the original inventor of the bullet now used with the Enfield rifle, and known as the Minié bullet, and for which Minié received the Government premium. Ezrgebirge, Saxony, March 28. Meetings for the Week. MON.-Royal United Service Institution.-"On Military Wm. Denison, 8. FRI. Royal United Service Institution.-"On the Architectural Association." Architecture of TO CORRESPONDENTS. striking inside the target, and penetrating 15 lin. The Bombay Gazette states that Colonel M. K. We regret to announce the recent death of Mr. William Baddeley, C.E., at the age of 61. Mr. Baddeley was, for many years, connected with the MECHANICS' MAGAZINE, and ultimately became a very large contributor to its pages, in which appeared his annual reports of the London fires. Mr. Baddeley had been connected with the London Fire Brigade ever since its formation by Mr. Braidwood. He was the original promoter of the London Society for the Protection of Life from Fire, and was for many years superintendent of the Society, having been latterly made an inspector. To mark their appreciation of Mr. Baddeley, the Society preThe MECHANICS' MAGAZINE is sent post-free to subsented him with the sum of £250, on his retir-scribers of £1 1s. 8d. yearly, or 10s. 10d. half-yearly, ing from the post of inspector, which he was able in advance. obliged to resign through age and infirmity. Mr. Baddeley was the originator of the movement which led to the adoption of inquiries into the causes of fires. He also brought out several important improvements in fire engines, including the hand engine, which is in use by the brigade to the present day. He was a most prolific inventor in various directions, chiefly, how. ever, in apparatus for the prevention or suppression of fires. He gave most of his inventions to the public, which they reached through the medium of our columns. Mr. Baddeley's last effort was the organisation of volunteer fire brigades in London, one of which-the Holloway brigade-is superintended by his son. It is said that screw-bolts of a very excellent description are being made in France, with the thread entirely forged, by some new process which the English makers have been unable to detect. As fastenings for armour plates they are stated to be invaluable. Advertisements are inserted in the MECHANICS' MAGAZINE at the rate of 6d. per line, or 5d. per line for 13 insertions, or 4d. a line for 26 insertions. Each line conrate as type. Special arrangements made for large advertisements. sists of about 10 words. Woodcuts are charged at the same All communications should be addressed to the EDITOR, 166, Fleet-street. To insure insertion in the following number, advertisements should reach the office not later than 5 o'ccolk on Thursday evening. We must absolutely decline attending to communica tions unaccompanied by the name and address of the RECEIVED.-R. L.-P. S. N.-Messrs. B. and B.- JOHN SIMPSON (Accrington).-The rule for ascertaining The Phare de la Loire has received communication of a very singular fact in a letter from Captain La Roche, dated Porto Cabello, Caracas, January It appeared that Captain Cadieras, 9th, 1867. commanding the schooner "Emilia," engaged in the coating trade, had found stranded on the coast of Curamichate, on January 6th, a vessel of 2,297 tona, dismasted, with the letters HIF on the stern, and freighted with deal planks. On one of these there was an inscription in French to the effect that the ship had been met at sea on May 4, 1865, by Captain Samson, of the "Mars," of Bordeaux, who, after a vain attempt to tow it along, had abandoned the task as hopeless. It follows that the vessel must have navigated itself without any crew during the twenty months between May, 1865, and Jannary, 1867, to drift ashore at last on the coast of Curamichate. |