M. TECHNOLOGY. 535 



English Mechanic, promises to be useful as a vehicle for 

 emollient preparations. It is a solid, semi-transparent jelly, 

 free from taste or odor, and becomes liquid at 93 Fahr. It 

 is obtained by evaporating crude petroleum, and filtering the 

 residue through animal charcoal. 18 A, Sex>t. 25, 1874, 36. 



TINNING VARIOUS METALS IN THE HUMID WAY. 



The following method is given by Wegler : A solution of 

 perchloride of tin is first prepared by passing washed chlo- 

 rine gas into a concentrated aqueous solution of tin-salt, and 

 expelling the excess of chlorine by gently warming it, then di- 

 luting it w T ith eight to ten times its volume of water, and fil- 

 tering it, if necessary. The article, well pickled in dilute sul- 

 phuric acid, and polished with sand and a steel scratch-brush, 

 and rinsed with water, is loosely wound with a zinc wire, and 

 immersed for ten or fifteen minutes, at the ordinary temper- 

 ature, in the dilute solution of perchloride of tin. When 

 tinned in this way, it is rinsed, brushed with a scratch-brush, 

 dried, and finally polished with whitening. This applies to 

 tinning cast iron, wrought iron, steel, copper, brass, lead, and 

 zinc. 13 C, November 1, 1874, 1368. 



GILDING GLASS. 



The following process for gilding glass has been patented 

 by Professor Schwarzenbach : A filtered solution of perfectly 

 pure chloride of gold, in boiling water, is diluted until twelve 

 cubic inches of the liquid contain one grain of metallic gold, 

 and is then rendered alkaline with caustic soda. As a re- 

 ducing agent, alcohol saturated with marsh gas, and then 

 diluted with its volume of water, is employed. One and a 

 half cubic inches of this liquid are added to the alkaline gold 

 solution, and the mixture then poured between the plate to 

 be gilded (previously well cleansed) and a glass plate placed 

 about one tenth of an inch below it. After remaining nn- 

 disturbed from two to three hours the gilding is complete, 

 and the glass is removed and washed. 16 C, November 26, 

 1874,428. 



NEW PHOSPHOR-BRONZES. 



Dr. Kunzel, whose name will be recalled as the joint dis- 

 coverer, with M. Montefiore-Levy, of the well-known phos- 



