CHEMISTRY. (INDUSTRIES.) 



169 



ascertain the maximum and minimum percent- 

 ages of alcohol and acetic acid which genuine 

 apple-juice will produce. Eight specimens of 

 cider made under the supervision of the author 

 from his own selection of apples, from the best 

 " August sweets " down to the poorest green- 

 ings, were examined. The best specimen gave 

 9'40 per cent, of alcohol; the poorest, 3 per 

 cent. The average of all the determinations 

 was 5 per cent., which may be taken as the 

 proportion of alcohol a good cider should con- 

 tain, while none should fall short of 4 per cent. 

 The two lowest grades of the cider, containing 

 respectively 3-85 per cent, and 3 per cent, of 

 alcohol, could not be protected from putrefac- 

 tive decomposition during the summer. The 

 six grades of cider higher than these two yield- 

 ed of acetic acid, the best lO'lO per cent., and 

 the poorest 4*45 per cent. The average was 

 6'18 per cent. The actual amounts of acetic 

 acid found were lower than the alcoholic per- 

 centages in the original ciders would demand. 

 This is explained by imperfect acetifi cation. 



" Nickel-plating," says Mr. William H. Wahl, 

 in a paper read before the Franklin Institute last 

 year, " is an American industry, in the sense 

 that it was first practiced on a commercial scale 

 in the United States, and here received that 

 practical demonstration of its usefulness that 

 has since made it the most successful and 

 most widely practiced branch of the art of 

 electro-plating." Its growth has been favored 

 by the success which Mr. Joseph Wharton 

 has attained in the production of metallic 

 nickel of suitable purity at a reasonable price. 

 Mr. Wharton was one of the first to work the 

 metal successfully, and exhibited at Vienna, 

 in 1873, samples of axles and axle-bearings, 

 and at Philadelphia, in 1876, a remarkable 

 series of objects of wrought-nickel. He pro- 

 duced in his works, between 1876 and the close 

 of 1882, 1,466,765 pounds of the metal, the 

 principal source of supply of which was from 

 the ores at Lancaster Gap, Pa. The ear- 

 liest practical process for nickel-plating in the 

 United States was patented by Isaac Adams, 

 Jr., in 1869. He devised a bath of the double 

 sulphate of nickel and ammonium and the 

 double chloride of nickel and ammonium, with 

 anodes of metallic nickel, in which iron was 

 combined, to obviate the bad effects of copper 

 and arsenic impurities. The extensive appli- 

 cation of this process was facilitated by the 

 production of nickel of improved qualities of 

 purity, and the introduction of dynamos for 

 producing the electric currents, they taking 

 the place of the expensive galvanic battery. 

 Edward Weston, in 1878, prepared a solution 

 containing boric acid, with the double sulphate 

 of nickel and ammonium, the superiority of 

 which is generally recognized. The deposited 

 metal is almost silver-white, dense, homogene- 

 ous, and tenacious, while the solution main- 

 tains a uniform, excellent working quality. 

 Other things being equal, the slower the rate 

 of deposition, the more adherent and tenacious 



the coating of deposited metal will be. Suc- 

 cess in plating depends very largely upon the 

 perfect cleansing of the articles before they are 

 immersed in the bath ; and this is more im- 

 portant in case of plating with nickel than with 

 other metals, for which the solutions are gen- 

 erally more alkaline. 



Mr. Jacob Baynes Thompson has devised an 

 improved process for bleaching, in which the 

 time usually required for that operation has 

 been greatly shortened. The main feature in 

 the process consists in the modes of chemicking 

 and souring under which the two operations 

 are performed simultaneously. Carbonic-acid 

 gas is employed as the decomposing or souring 

 agent, and a solution of triethylroseaniline and 

 oxalic acid is employed to remove the faint 

 natural yellow tinge of the cotton. * In carry- 

 ing out the Thompson process, the goods are 

 first boiled in an alkaline solution and washed. 

 They are then placed in an air-tight kiln con- 

 nected on the one hand with a vessel contain- 

 ing the bleaching solution, and on the other 

 hand with a gas-holder containing carbonic-acid 

 gas. After the bleaching solution has remained 

 long enough in the kiln to enable the material 

 to be thoroughly soaked, about five minutes, 

 the liquor is drawn oif and the gas is let in, to 

 remain in contact with the moistened material 

 till it has decomposed the whole of the chloride 

 of lime in the bleaching solution on the fiber 

 of the cloth, or for about forty-five minutes. 

 The bleaching - liquor is again run in, to be 

 succeeded again by the carbonic acid, till the 

 material is of sufficient whiteness. Then the 

 material is thoroughly washed, after which it is 

 slowly passed through the solution of triethyl- 

 roseaniline, when the process is complete. The 

 time required ranges from eight to twelve hours, 

 according to the nature of the fabric under 

 treatment. 



Dr. L. Ehrlich has for the first time suc- 

 ceeded in isolating gallium by an industrial 

 Srocess. He followed the method of M. L. de 

 oisbaudran of extracting it from zinc-blende, 

 with a few modifications. When operating on 

 several hundred-weight of blende, he succeeded 

 in simplifying the process so that it became pos- 

 sible, within two or three days after lixiviation 

 of the zinc sulphates, to concentrate the gal- 

 lium of six hundred- weight of blende in a rela- 

 tively small quantity of a mud containing fer- 

 ric oxide. On the electrolysis of the galliferous 

 alkaline solution, the metal was deposited on 

 the negative electrode in fine needles of from 

 two to three millimetres in length. After wash- 

 ing the electrode with water and alcohol, the 

 metal, when being dried near a flame, could be 

 melted into small globules at a temperature of 

 30-5 0., or about 87 Fahr. The luster of gal- 

 lium-globules is greater than that of mercury. 



MM. Brin, of Passy, are producing oxygen 

 on a large scale by the barium-oxide process 

 and applying it to the purification of water. 

 For this purpose filtered water is placed in a 

 cylinder and saturated with oxygen gas at three 



