Association for the Advancement of Science. 469 



Mr. J, W. Rogers read a paper on the Chemical Properties of 

 the Potato, and its Uses as a General Article of Commerce if 

 properly manipulated. The object of this paper was to show 

 that the matter of the potato was in reality equal in nutritive 

 value to the dry matter of wheat, whilst the quantum of food pro- 

 duced from a given quantity of land was nearly four times that 

 produced from wheat. He exhibited some very interesting speci- 

 mens of the produi;tion of the potato in meal, flour, &c., and gave 

 the following results of analysis : — 



Starch. Gluten. Oil. 



Components of the potato per cwt. 84.0*7'? lb. 14.818 lb. 1.104 lb. 

 Do. of wheat, do. T8.199 " lT.536 " 4.265 " 



And gave the following results as to the quantum of food from 

 an acre of land : — 



starch. Gluten. Oil. 



Dry matter of potato, - - - - 3421 lb. 604 1b. 45 1b. 



Dry matter of wheat, - - - - 825 " 185 " 45 " 



The concluding communication was made by Dr. Gilbert 

 being a Preliminary Notice of Researches on the xissimilation of 

 Nitrogen hy Plants^ by 3fessrs. Lawes, Gilbert, and Pugh. The 

 great importance of settling the question, Whether or not plants 

 can assimilate the free nitrogen of which the atmosphere to such 

 an extent consists ? was first insisted upon. In a purely scientific 

 point of view the question was of high interest, and if answered 

 in the aflarmative this would add a very striking fact to the his- 

 tory both of nitrogen itself and of the vegetable functions. A 

 true theory of many^agri cultural facts and practices also required. 

 a definitive solution of this debated point. Earlier writers sup- 

 posed that the free nitTogen of air could be taken up by plants. 

 De Saussure and others came to an opposite conclusion ; and this 

 latter view had been pretty generally adopted by scientific ob- 

 cervers. Boussingault in particular had brought experimental 

 evidence to show that plants did not assimilate the nitrogen of 

 the air. But during the last few years a most elaborate and ex- 

 tensive series of investigations had been made by M. G, Ville of 

 Paris, the results of which led him to conclude that plants assimi- 

 lated a considerable amount of free nitrogen. M. Boussingault 

 had followed up the inquiry in various ways, and still maintained 

 the opposite opinion. It was hence of the highest importance 

 that a third party should undertake the subject, and it was to 

 this end, and the results so far obtained, that the authors brought 



