1869.] Chemistry. 427 



a product of alizarine, SIM. Graebe and Liebermann have since 

 succeeded in solving the inverse problem, that is to say, the arti- 

 ficial preparation of aUzarine by means of anthracene. They con- 

 vert that hydrocarbon into alcohol, and the alcohol into an acid 

 (lizaric acid and alizarine being synonymous), by acting upon the 

 hydrocarbon with chlorine or bromine, and next eflecting a double 

 decomposition by means of acetate of potassa and caustic potassa ; 

 after which an oxidizing agent is again made to act upon the 

 alcohol so obtained. The properties of the product, as well as the 

 colours which it has given on mordaunted cotton, prove the com- 

 plete identity of artificial alizarine with that from madder root. 



Professor G. Hinrichs has described the following ingenious 

 way of preserving sodium untarnished as a lecture specimen. — 

 Take two test-tubes, one a little smaller than the other, so as to 

 slip into the latter without leaving much space between the two 

 glass walls ; put some carefully-cleaned sodium in the wider tube, 

 insert the more narrow tube, having previously given a thin coating 

 of beeswax to the upper part of this latter, then gently heat the 

 whole on a sand-bath. The sodium will fuse, and by a gentle 

 pressure, the inner tube is pressed down, so as to force the fused 

 metal over a large surface between the two tubes, while the air is 

 totally excluded by the beeswax. Sodium has been kept for more 

 than six months in this way as bright and brilliant as when first 

 put up. 



It is well known that hydrochloric acid is used for the pur- 

 poses of dissolving the earthy salts of bones, in order to obtain 

 the gelatine they contain in such a state as to render that sub- 

 stance readily soluble in boiling water. The use, however, of 

 hydrochloric acid is rendered rather inconvenient for this purpose, 

 on account of the formation of chloride of calcium, which interferes 

 with the drying of the gelatine. M. Coignet, at Paris, has found 

 that sulphurous acid answers the purpose of hydrochloric acid in 

 this instance perfectly well. The bones are placed in cold water, 

 and through the water a current of sulphurous acid gas is forced, 

 so long as is required to completely soften the bones, which are 

 afterwards washed in fresh water wherein some sulphurous acid 

 gas has been previously dissolved. 



Professor Horsford, of Yale College, has tried to detect fluorine 

 in the human brain; he was induced to do so by the fact that 

 fluorine so frequently accompanies phosphoric acid in the mineral 

 kingdom, and also on account of the large proportion of phosphoric 

 acid found in the brain and nerves by Yon Bibra and others. After 

 having very carefully ascertained that the reagents he was about to 

 apply were quite free from fluorine, the learned professor operated 

 upon a human brain which had been long kept in spirits of wine, 



VOL. VI. 2 G 



