214 SCIENTIFIC APPARATUS. 



sending a large number of preparations, organic and inorganic, 

 many of which are of great interest. 



The great chemical industries of this country are well repre- 

 sented. Professor Roscoe sends some models of the plant of 

 alkali works, which cannot fail to be of great value in instruction 

 in a large industrial city. The modes of preparation of chlorine 

 for the manufacture of bleaching powder, by the process of Mr. 

 Weldon, is illustrated by diagrams, and also by some specimens 

 of the materials at different stages of the process. Mr. Deacon 

 sends a model of his apparatus for the manufacture of chlorine 

 direct from the gases of the salt-cake furnaces. Various products 

 from the alkali works are exhibited by Messrs. Hutchinson and 

 Co., Messrs. Gaskell, Deacon, and Co., and Messrs. Sullivan and 

 Co. Specimens of sulphur recovered from the alkali waste by 

 Mond's process are shown by Messrs. Hutchinson. Another 

 important use of waste products is the recovery of copper and 

 silver from the residue from the pyrite burners in the oil of vitriof 

 factories by the Widnes Metal Company. A number of alkaline 

 silicates are exhibited by Messrs. Gossage and Sons, and a series 

 of specimens illustrating the mode of manufacturing alum from 

 shale by Mr. Spence. 



The production of colours from aniline, and other coal-tar 

 derivatives, is exemplified by a large number of specimens of 

 mauvine and its salts by Mr. Perkins, and of aniline reds, blues, 

 violets, and greens by Messrs. Brooke, Simpson, and Spiller. 



H. Me LEOD. 



