302 Proceedings of Learned Societies. 



tern, is allowed to pass into the arteries, thence through the capil- 

 laries, into the veins, and to escape by means of the orifice in the 

 venous side of the heart ; in this manner the entire blood is washed 

 out of the body, after which a solution of salt and sugar is injected 

 as a preservative liquid. Similar plans were the subjects of patents 

 taken out more than twenty years since, and were not found to suc- 

 ceed in practice. The theoretical objections appear to be, firstly, 

 that by washing the blood out of the capillaries, the nutritive power 

 of the meat is very much lessened ; and secondly, that the preserva- 

 tive effect of the plan proposed is very doubtful. The antiseptic 

 effect of salt is in great part owing to its power of abstracting 

 water ; this is not possessed by brine. It was stated that the meat 

 preserved by Dr. Morgan's process was, when packed in barrels for 

 ship use, headed on with a great amount of dry salt ; this would 

 have the same effect as the salt used in the ordinary plan of salting, 

 and would slowly abstract the juice of the flesh, and render the 

 meat as dry and innutritious as the ordinary plan. 



ROYAL INSTITUTION.— April 15. 



Eecent Discoveries respecting the Properties of Gun-cotton. — 

 Professor Abel delivered a most interesting lecture on the prepara- 

 tion and properties of gun-cotton ; the lecture included a description 

 of those recently discovered modifications, dependent on mechanical 

 aggregation, which have enabled gun-cotton to be introduced with 

 success in warfare, and for blasting purposes. 



After detailing the objections to gun-cotton as ordinarily manu- 

 factured, objections which have hitherto precluded its use in actual 

 service, Prof. Abel explained the action of nitric acid on cotton. 

 He showed that it has two distinct modes of operation. If the 

 nitric acid be permitted to act at a high temperature, and in an 

 energetic manner, the carbon and hydrogen of the cotton may be 

 completely oxidized. When, however, the action is moderate, and 

 the temperature kept low, the hydrogen only is assailed, and is re- 

 moved in gradations, peroxide of nitrogen being substituted for it. 

 When two atoms of hydrogen are removed, and two equivalents of 

 peroxide of nitrogen substituted, xyloidine is produced. When 

 three atoms of each axe interchanged, trinitro-celluloso, or puro 

 gun-cotton is the result — 100 parts of cotton losing 1*85 of hydrogen, 

 and receiving 85*12 of peroxide of nitrogen, Intermediate stages 

 may also bo brought about, as in the preparation of that variety of 

 gun-cotton used in the formation of collodion. 



Tho original directions of the discoverer, Schonbein, order 

 the nitric acid employed to bo mixed with strong sulphuric acid, 

 but from want of the requisite precautions in the manufacture, the 

 product was uncertain m properties, sometimes even exploding 

 spontaneously. J'y the precautionary measures adopted in the 

 Austrian army, these uncertainties have been obviated. 



The cotton loosely spun into yarn is boiled in a weak solution of 

 alkali, in order to remove more easily oxidized materials, whose pre- 

 sence interferes with the action of the nitric acid. After this washing 



