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POPULAR SCIENCE REVIEW. 
Manager of the French Mint. — The post of Director of the Paris Mint, 
vacant by the death of M. Pelouze, has been given to M. Dumas, the eminent 
chemist. M. Dumas had previously resigned his appointment of professor in 
the faculty of science of the University of Paris, and inspector-general of 
the high schools of France. 
Cause of the JDecolorisation of Iodine Starch. — In a paper, published in the 
Bulletins de la Societe Chimique , M. Pellet states the following conclusions as 
the results of his experiments in the cause of the deeolorisation of the 
iodine starch, and the reappearance of colour on cooling : — 1. Deeolorisation 
is caused by the solution of iodine starch in an excess of hot starch ; the solu- 
bility being less in the cold, the colour reappears again on cooling. — 2. 
Iodine starch is decomposed at 100°C,'aud iodine volatilises. — 3. Iodine 
starch remains unchanged in alcohol, being equally insoluble in that liquor 
whether hot or cold. — 4. Iodine starch may be regarded as a salt, which in 
certain solvents is more readily soluble when hot, than when they are cold. 
Silicates of Methyl. — In a recent number of Silliman’s American Journal , 
there appears the following account of the mode of preparing the above 
compound. It was first attempted, by Messrs. Friedel and Crafts, to prepare 
the silicate by reacting on methylic alcohol with chloride of silicium ; like 
Ebelmen, they obtained a product impossible to purify, turning brown in the 
air, and possessing a foetid odour. They noticed that this product always 
contained chlorine. Wood-spirit was purified by treatment with chloride of 
calcium ; the chloride of calcium compound decomposed with water, and the 
alcohol rectified several times with sodium. The alcohol thus prepared was 
sealed in a tube with silicate of ethyl, and the mixture heated during 20 
hours at 210°C. After several fractional distillations, the principal product 
isolated from the contents of the tube was a liquid boiling at 143° to 147°. 
This liquid gave on analysis numbers which correspond with the composition 
of a mixed silicate, diethylic, dimethylic, silicic ether. There being reason 
to believe that a minute trace of water contained in the methylic alcohol 
interfered with the success of the processes in which it was employed, this 
alcohol was distilled twice with sodium, then with a small quantity of 
anhydfous phosphoric acid. Thus prepared, it boils at 65*5°, has not the 
disagreeable odour it usually has, smells like common alcohol, and does 
not turn brown with soda. Methylic alcohol purified in this way, when 
added to chloride of silicium, reacts like ordinary alcohol. When the 
theoretical quantity of the alcohol has been added, the product is distilled, 
and after a small number of fractional distillations two principal products 
are obtained, one boiling at 120° to 122°, and the other at 201° to 202-5°. 
The first is the normal silicate of methyl •, the second is the hexamethylic 
disilicic ether. The normal silicate of methyl is a colourless liquid, has 
rather an agreeable odour, is soluble in a considerable quantity of water. 
Moisture or aqueous alcohol gives rise to condensed products, ultimately 
silica. It burns with a white smoke composed of silica. 
Crookesite , a Neio Thallium Mineral. — A mineral, rich in thallium, has been 
discovered by M. Nordenskiold, in Mosander’s collection, and has been named 
Crookesite, in compliment to Mr. W. Crookes, F.D.S., the discoverer of 
thallium, and the accomplished editor of our contemporary the Chemical 
News. Crookesite forms small, coherent, opaque masses, of metallic lustre, 
