142 Royal Society. 



therefore be a little less than a quarter of theirs. The valves 

 would have to be altered to give compression iu the ingress 

 cylinder during the same fraction of the stroke as that required 

 for expansion when the air is heated through the same range of 

 temperature, and the valves of the egress cylinder would have to 

 give the same proportion of expansion as is given of compression 

 in the other case ; and the jiressure kept up in the receiver by 

 the action of the pistons thus arranged would be 1^# atmospheres, 

 or about 3'2 lbs. on the square inch above the atmospheric 

 pressure. The principal cylinders being of the same dimensions 

 as those assumed above, and the quantity of air required being 

 the same (1 lb. per second), the pistons would have to be worked 

 at only 34'6 double strokes per minute instead of 30, and the 

 horse power required would be '288, instead of as formerly "283, 

 when the same machine was used for giving a supply of heated air. 



XXI. Proceedings of Learned Societies. 



ROYAL SOCIETY. 

 [Continued from p. 68.] 

 Dec. 8. 1853.— Colonel Edward Sabine, R.A., V.P. and Treasurer, 

 in the Chair. 



THE following paper was read :— " On some of the Products of 

 the Decomposition of Nitrotoluylic Acid." By Henry M. 

 Noad, Ph.D., Lecturer on Chemistry at St. George's Hospital..; 



The author refers to a former memoir in which he described the 

 mode of preparation and properties of two new organic acids, the 

 analogues of benzoic and nitrobenzoic acids in the toluyl or im- 

 mediately succeeding series, and to which the names of toluylic 

 (C,8 Hs O44) and nitrotoluylic (Cj,; H^ (NO4) O4) acids were con- 

 sequently given. 



In the present paper he resumes the study of the action of nitric 

 acid on cymol (C00H14), and describes first some unsuccessful 

 attempts to procure from that oil the substitution compound 



r H ) 



Cgo \ >jQ \ > from which, by the action of reducing agents, he had 



hoped to procure a new organic base homologous with aniline, 

 toluidine, &c. He then investigates the products of the decompo- 

 sition of his new nitrogen acid. He describes the preparation and 



properties of nitrotoluylamide Ciq < ^'L > O4, NHj, and having 



succeeded, though by a rather tedious process, in obtaining this 

 substance in some quantity, he studies the action of reducing agents 

 on it. By the action of hydrosulphate of ammonia upon an aqueous 

 solution of the amide, a crystalline substance was procured, which 

 analysis proved to be homologous with the carbamide — carbanilide of 

 Hofmann, and with the unilo-urea of Chancel. The study of its 

 properties showed that it must be considered as the analogue of the 



