Chemistry and Physics. 267 



friction might be expected to obtain, and by such molecular friction 

 heat might be produced. In proving the correctness of these conjec- 

 tures difficulties presented themselves, the principal of which was that 

 with electro-magnets the heat produced by the electrized coil surround- 

 ing them might be expected to mask any heat developed by the mag- 

 netism. This interference the author considers he eliminated by sur- 

 rounding the poles of an electro-magnet with cisterns of water, and by 

 this means, and by covering the keeper with flannel and other expedients, 

 he was enabled to produce in a cylindrical soft-iron keeper when rapidly 

 magnetized and demagnetized, a rise of temperature several degrees be- 

 yond that which obtained in the electro-magnet, and which therefore 

 could not have been due to conduction or radiation of heat from such 

 magnet. By filling the cisterns with water colder than the electro-mag- 

 net, the latter could be cooled while the keeper was being heated by the 

 magnetization. The author subsequently obtained distinct thermic 

 effects in a bar of soft iron placed opposite to a rotating permanent steel 

 magnet. To eliminate the effects of magneto-electrical currents, the 

 author then made experiments with non-magnetic metals and with silico- 

 borate of lead, substituted for the iron keepers, but no thermic effects 

 were developed. He then tried the magnetic metals nickel and 

 cobalt, and obtained thermic effects with both, and in proportion to their 

 magnetic intensity. Some questions of theory relating to the rationale 

 of the action of what are termed "the imponderables" and to terres- 

 trial magnetism then were discussed ; and the author concluded by 

 stating that he considers his experiments prove, that whenever a bar of 

 iron or other magnetic metal is magnetized its temperature is raised. 



4. Glonoine. — It is now more than two years since M. Sobrero 

 first announced the discovery of this body by the action of nitro-sul- 

 phuric acid upon glycerine.* When a mixture of two volumes of sul- 

 phuric acid, sp. gr. 1*838, and one of nitric acid of 1*43, is surrounded 

 by a freezing mixture, and syrupy glycerine is slowly added with con- 

 stant agitation to prevent an elevation of temperature, it dissolves with- 

 out any escape of gas. From this solution, water precipitates the new 

 compound in the form of a heavy yellow oil which may be washed 

 without loss, as it is quite insoluble in water. By solution in alcohol 

 m d precipitation by water, it is obtained pure with the exception of a 

 "file moisture which may be removed by exposing it in vacuo over sul- 

 phuric acid. It is inodorous, but sweet, pungent and aromatic to the 

 taste. The smallest portion placed upon the tongue was found to pro- 

 1 duce a violent headache, and the discoverer recommends the greatest 



care in its preparation. He did not submit it to analysis, but from the 

 mode of its formation, it is probably a nitric species of glycerine. 



The physiological action of this substance is most extraordinary ; the 

 observations of i\[. Sobrero havin* attracted the attention of Dr. Henng 

 of Philadelphia, he with some Jther medical gentlemen of that city 

 nave made a series of experiments with it, upon men and the lower 

 animals.t As the discoverer had not named the new body, Dr. Henng, 





See Chem. Gazette, May, 1847. from Compt. Uendus, Feb 17th, 1847. 

 . t American Journal of HomtBopathy, May, 1 849, from which, m part, the toUow- 

 »ng details are taken. 



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