216 



CHEMISTKY. 



in comparisons of the sort here considered, the 

 author suggests 100C.,=212 F. 



The researches on several of the homologous 

 series of organic bodies are still going forward, 

 the number and relations of the substances 

 formable in such series being as yet subject to 

 indefinite extension. For these researches and 

 the new compounds developed in them, as 

 well as some others, the reader must be referred 

 to the chemical journals. 



VIII. APPLICATIONS OF CHEMISTRY. It has 

 been, of course, impossible to present the pre- 

 ceding more theoretical topics without refer- 

 ence under some of them to applications in 

 the arts or otherwise ; but the subjects follow- 

 ing are such as possess more purely a practical 

 bearing or value. 



Webster's Oxygen Process. In this is em- 

 ployed a furnace containing a strong cast-iron 

 vessel 10 inches in diameter, in which is placed 

 a smaller one V inches in diameter, open at the 

 top, and provided with an orifice at the base, 

 temporarily stopped with sheet-iron : when its 

 contents are exhausted, they can be beaten out 

 through this with an iron bar. The outer 

 vessel is connected by a pipe with a 30-gallon 

 stone-ware vessel, containing gallon of water, 

 and 8 stone- ware colanders, upon which is 

 placed 48 Ibs. of the residue of a previous ex- 

 periment, to serve as a purifier. The inner 

 pot is charged with 10 Ibs. of warm dry nitrate 

 of soda, and 20 Ibs. of warm dry crude oxide 

 of zinc, the latter obtained from the so-called 

 galvanic baths. A cover is luted on, and heat 

 applied sufficient to give to the mass a pasty 

 character. Oxygen is speedily given off, with 

 nitrous fumes ; these the purifier absorbs. By 

 the process, a large quantity of oxygen is ob- 

 tained at small cost, but mixed with nitrogen 

 to the extent of .41. For many uses, as in the 

 various metallurgic processes, this intermixture 

 is in no way detrimental ; and it is even sup- 

 posed capable of augmenting the illuminating 

 power of coal gas which the oxygen may be 

 employed to consume. 



Potash from the Animal Kingdom. Hitherto 

 the supply of potash has been obtained mainly 

 from vegetable sources. Eecently M. Maumene, 

 a French chemist, has obtained this alkali in 

 considerable quantity from an animal product, 

 the yolk, or oily soap, naturally secreted along 

 with the growth of wool, and usually consti- 

 tuting from \ to , or even more, of the entire 

 weight of the unwashed fleece. The fleeces 

 of sheep's wool sheared without washing or 

 pulled, are submitted to action of cold water 

 in a tank or reservoir, and the yolk, which is 

 a combination of fatty and oily acids with pot- 

 ash, readily dissolves out of them. Separating 

 the soap, and heating it to redness, a very 

 pure carbonate of potash is obtained. The 

 process is so productive, that it is already 

 worked as a commercial speculation at Eheims, 

 and samples of the potash salts were shown at 

 the International Exhibition. 



Copper Paint. The Abbe Moigno describes, 



in the " Cosmos," a new pigment which has 

 come into use in the workshops of M. Oudry, 

 of Autenil. Copper set free from some of its 

 salts by the electrolytic process, is reduced to 

 an impalpable powder, and mixed with benzine : 

 this may be employed on any surface as a paint. 

 It possesses an agreeable lustre, and takes 

 bronze tints by the usual means. By reducing 

 the quantity of copper, and adding bases of 

 lead, zinc, or other suitable metal, M. Oudry 

 has produced a series of paints said to possess 

 great advantages over the ordinary prepara- 

 tions with turpentine and oils. 



Aluminium Uronzefor Philosophical Instru- 

 ments. Lieut.-Col. A. Strange, having to super- 

 intend the construction of some astronomical 

 and geodesical instruments of large size, for 

 the Trigonometrical Survey of India, and 

 the instruments requiring to be transport- 

 ed over ground very unfavorable for such 

 carriage, was about to have certain parts usually 

 entire cast in separate portions, when his 

 attention was called to some articles in the 

 International Exhibition, made from alumin- 

 ium bronze, and which were from the works 

 of Bell Bros., of Newcastle, and M. Morin, of 

 Paris. He proceeded to have careful series of 

 experiments conducted by different parties with 

 a view to testing the qualities of this bronze ; 

 his summing up of the results attained being 

 communicated to the Astronomical Society, 

 and appearing in its "Notices," Nov. 1862. 



The alloy named was first made by Dr. Percy, 

 about 6 years since. It is composed of the metals 

 aluminium and copper in various proportions ; 

 the alloy of 10 parts aluminium to 90 of cop- 

 per giving the best material for most mechani- 

 cal purposes. The twelve qualities regarded 

 by Mr. Strange as most essential in a metal for 

 the making of astronomical and other philosoph- 

 ical instruments, will be named in order, and 

 the results in the several particulars obtained 

 in respect to the aluminium bronze will be 

 briefly noted under each. 1. Absolute or ten- 

 sile strength. The aluminium bronze in good 

 bars broke with a weight of 73.185 Ibs. to the 

 sq. in. section ; gun metal, at 35,040 Ibs. ; while 

 an average quality of steel breaks at about 80,- 

 000 Ibs., some qualities however ranging much 

 higher. 2. Resistance to compression. The 

 bronze showed no perceptible compression 

 until the load upon it reached 20,384 Ibs. per 

 square inch; then it suddenly yielded .006 of 

 an inch, regaining .001 when the load was re- 

 moved. Its ultimate compression, or the load 

 at which it yielded so as wholly to lose its 

 form, preparatory to crushing, was 132,416 

 Ibs. ; while the ultimate compression of cast 

 iron is about 115,542 Ibs. The bronze is thus 

 exceedingly hard and incompressible. 3. Mal- 

 leability. This is excellent : the alloy is malle- 

 able almost up to melting, and it can be drawn 

 under the hammer almost to a needle point. 4. 

 Transverse strength, or rigidity. On this qual- 

 ity the perfection of astronomical instruments 

 is more dependent than on any other singly. 



