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GALVANIC MACHINE AND BATTEBIES—PLATINA ALEMBIC.
[Class; X.
Statham (No. 456, j>. 463). Boxes fitted with chemicaltests, in various sizes, pneumatieal troughs, See.
Baker (No. 396, pp, 451,452) exhibits a saccliarometerand lactometer ; but it is to be remarked, with respect tothe former instrument, that the optical analysis of sugarsurpasses all other modes.
Coffey (No. 454, p. 463) exhibits chemical apparatus.In a few square feet are composed the means of perform-ing some of the most important and troublesome opera-tions of the laboratory. It contains a still vor steam-boiler), with sets of moveable pans for decoctions, ex-tracts, evaporations, steam-baths for retorts, stills, See.,drying-closet, a condenser for steam, and worms forother stills, the chamber containing them acting also as astove and condensing tube. The temperature can beregulated with great exactness, by means of steam-cocksand valves. An improved feeder, a steam-gauge andthermometer, a safety-valve and alarum, are attached tothe boiler.
Johnson and Mattiiey (Class I., No. 477, p. 161) haveexhibited palladium crucibles and capsules. The use ofpalladium for this purpose has many advantages. Itsinfusibility, though not so great as that of piatina, is suchas to enable it to resist the greatest heats applied in allordinary chemical operations, while it is not subject, aspiatina is to a considerable extent, and gold, in somedegree, to be attacked and corroded by the caustic alkalisat high temperatures. It is much less fusible than goldor silver, and, like the former, resists the action of allacids. For this valuable accession to the list of chemicalutensils a Prize Medal was voted.
[It may not be irrelevant to the subject of this report,to suggest as worthy the attention of chemists, the practi-cability of coating, by galvano-plastic processes, theinterior of clay or plumbago crucibles with films ofpiatina, palladium, gold, or even silver (as the use towhich they are to be applied may require), of sufficientthickness and cohesion to withstand a moderate amountof mechanical abrasions, and to intercept the action ofsaline matter in fusion on the crucibles. Much of theoriginal cost, both of material and fabrication, would thusbe saved, and the material might be recovered by acidsfrom the worn-out or broken utensils.—J. F. IV. II.]
Horne, Tiiorntiiwaite, and Wood (No. 220, pp. 434,435) exhibit a galvanic machine for medical and otherpurposes, with a case of instruments for its application.The novelty of its construction, and that upon which itsutility depends, is, that the current of electricity producedshould be of considerable intensity, and flow in onedirection only. It is composed of one coil of stout insu-lated copper wire. A Smee’s voltaic battery, with anarrangement for lifting the plates out of the acid whennot in use; and a balance galvanometer, for indicatingthe strength of galvanic currents by means of grainweights.
Hearder (No. 439, p. 461) has exhibited a galvanicmachine, with a graduated regulator employed to ad-minister galvanic electricity. It is intended to regulatethe intensity of the shock by means of two moveable in-dices; that on the left by advancing over a graduated arcproduces equal increments of power, that on the right bymoving over an arc which subdivides the increments ofthe first index into four parts, makes the advance fromone extreme to the other gradual. The difference of con-struction consists in the proper adjustment of the lengthand thickness of the generating or primary coil to theelectro-motive force of the battery, by which the batterysurface is much reduced, and a higher degree of magnet-ism produced in the iron core. The instrument is com-pact, the bottle of dilute acid being contained in the boxof requisites. The high magnetic power permits the useof strong springs which vibrate rapidly: the great rangeof power is also equally divided. It is the invention ofMr. Hoarder, of Plymouth, and is intended for the use ofprivate families. It may be mentioned that a differenceof construction has been resorted to for the purpose of in-creasing the attractive power by means of a small ironrod in the centre of the core, which is employed to exerta more powerful attraction upon the iron armature of thespring, the shape of the armature itself being peculiar.
Taylor (No. 466, p. 4G4) exhibits a pneumatic batteryfor igniting gunpowder in blasting operations.
Nunn (No. 371, p. 450) exhibits a hydrometer,capable of ascertaining the specific gravities of all fluids,its range including 0*6 to 2*0. The point of most in-terest in this instrument consists in the being able to in-sert certain weights with the instrument below the centreof gravity, thereby rendering its uniform bulk of anyspecific weight that may be required. By this meansconsiderable accuracy and efficiency are obtained.
Lyons (Class VI., No. 203, p. 291) exhibits severalbatteries, and claims improvement for his introduction ofwood instead of porous cells, which by rendering thedeposition of copper more regular in its action, and moreconstant in its deposition, constitutes an arrangement bywhich no copper is lost. In consequence of the action ofthe sulphate of copper being limited to the surface ofporous cells, holes were made in the cells, so that thesolution becoming acidulated, acted upon the copper:Mr. Lyons, to obviate this, introduced a gutta-perchatube, perforated with holes, and found the copper clearand equal throughout, also the solution of equal strengthboth at the top and bottom.
The principle here exhibited is that of economizing thebattery power.
Mr. Lyons lias also introduced methods by which hemakes the usual waste available for battery power, by havingtwo cells of gutta-percha, the one fitting within the other,charged with aquafortis ; by the introduction of plates ofiron on either side, with zinc in the centre, and suitablearrangements, he saves the oxide of copper by its beingthrown down. Mr. Lyons has the merit of arrangementswhose objects are constant and regular action, cheapness,and suitability to the performance of all that to whichelectro-magnetism is usually applied.
Qukxnesskn (France , No. 1683, p. 1257). This ex-hibitor stands first in the exhibition of chemical apparatus,having exhibited a piatina alembic for sulphuric acid,containing 250 pints, nwde in one piece, without senn orsolder ; also long piatina tubes, made without seam, be-sides crucibles, capsules, &c., all of which are executedwith the greatest care, and appear to be of the mostfinished and exquisite workmanship. Among the articlesin piatina exhibited by M. Qucnnessen is an apparatusfor the distillation of hydrofluoric acid, of a very completeand perfect kind. A Council Medal was awarded toM. Qucnnessen.
Chuaiid (France, No. 123, p. 1177) exhibits a gazo-scope, an apparatus so constructed as to indicate thepresence of hydrogen gas, when in an atmosphere con-taining only ^th part of this gas, that is to say, 1 partof gas to 179 of atmospheric air.
In the year 1843, several engineers were appointed totest the gazoscope, in the coal-mines of St. Etienue, andthey reported favourably upon its efficacy in preventingexplosions of all kinds during the time of trial, viz.,during the months of October, November, and December,1843. According to Sir Humphry Davy , the proportionnecessary to an explosion is about -j'^th; and, conse-quently, if the presence of so small a portion as T l 5 thcan he shown, its presence would he made manifest longbefore an explosion could take place.
M. Chuard also exhibits a new safety-lamp, which hasbeen made at the expense of the Board of Health at Paris ,for the use of establishments containing spirits, essences,ether, or any kind of volatile and inflammable substance.It possesses the advantage of having no wire gauze andis filled by a tube. It extinguishes itself when the gasbecomes explosive, and is inexpensive. The constructionof this lamp is very ingenious, and the Jury regret (it nothaving been patented) their not being at liberty to de-scribe it.
M. Chuard also exhibits a lamp for chemical purposes,&c.
The Jury awarded the Prize Medal to M. Chuard forhis safety-lamp.
Bonnet (France , No. 1096, p. 1230) lias exhibited anassay furnace and a small assortment of crucibles of whiteclay. Also a small melting furnace, remarkable for thefacility with which it can be taken to pieces and cleaned.