502 TRANSACTIONS OF THE AMERICAN INSTJTUTS. 



It has a specific gravity of 0.025, and is the lightest of all known 

 liquids. Dr. Richardson of London, liad used ether in an appara^ 

 tus of his own coHstruction, lately exhibited before this Society, by 

 which the temperatm-C' was reduced to ^^bel^w zero F. Dr. Biglow 

 by a more simple contrivance is enabletl to apply rhigolene so as 

 to produce easily a temperature from 15° to 19° belaw zero. The 

 warmth of the hand holding the phial containing rhigoleHe is suf- 

 ficient to produce the vapor. Freezing is thus far more sure thau 

 by ether, boiling at 96° instead of 70°, sometimes fails to produce 

 the adequate degree of cold. In small surgical operations this 

 cheap, active and inofieusive but highly intlammable hydrocarbon 

 will be foOBcl of good service. 



GUNPAPEE, 



This article consists of paper impregnated wJth a composition 

 formed of the following ingredients: Chlorate of potash, nine 

 parts; nitrate of potash, four and a half parts; prussiate of potash, 

 three and a quarter parts; poAvdered charcoal, three and a quarter 

 parts; starch, one twenty-first part; chromate of potash, one six- 

 teenth part; and water seventy-nine parts. These materials are 

 mixed together and subjected to an hour's boiling; the solution is 

 then ready for use, and the i^aper is passed in sheets through the 

 mixture. The saturated paper is now ready for manufacturing 

 into the form of a cartridge, and is rolled into compact lengths of 

 any diameter, from that of a small revolver to that of a 600- 

 pounder. 



After rolling, the paper is dried at a temperature of 212° Fah.^ 

 when it presents the appearance of a compact greyish mass, re- 

 sembling nothing so much as a piece of vulcanised india-rubber 

 door spring. 



It is readily protected from all chance of damp by a solution of 

 xyloidin in acetic acid. The xyloidin is prepared by acting on 

 paper with nitric acid, one part thereof being dissolved in three 

 parts of acetic acid of specific gravity of 1.040. 



Electro-magnetic Chain of Metallic Filings. 

 An interesting experiment is described by M. Cauderay of 

 France. An electro majjnet is introduced into the circuit of a 

 galvanic file, the circuit is broken at any point, and the ends of 

 the wires are separated one from the other in a box containing 

 flings of silver, copper, brass, or iron, These metallic particles 



