

M. Becquerel on Chemico-cnpillary Actions, 437 



must be possible ; the action 2 CO + C = C0 2 + C has already been 

 observed by Deville, who obtained carbonic acid when he passed 

 carbonic oxide over red- hot charcoal. 



The author obtains the following numbers for the oxides of 

 nitrogen, which express in thermal units the excess of the energy 

 of the compound over that of its constituents : — 



NO - 8724 



NO 2 < 22968 



NO 3 < 16354 



NO 4 < 35468 



NO 5 < 43623 



Here NO 3 and NO 5 are assumed to be in solution. It follows 

 from these numbers that the aqueous NO 5 is the most stable — 

 moreover, that NO 4 is far more permanent than NO 2 . Anhy- 

 drous NO 5 has a different deportment; it dissolves in water 

 with considerable disengagement of heat, and therefore has more 

 energy than aqueous NO 3 . Hence also NO 2 could never form 

 NO 5 with oxygen except in presence of water ; NO 2 and O can 

 only form one product of less energy. Such a case is the NO 4 

 here formed. 



The sudden ignition of many bodies when heated, for instance 

 chromic oxide, Gadolinite, Samarskite,&c, the author explains on 

 the supposition of a sudden change in the energy. Many bodies 

 occur in two conditions with different energy. Yellow iodide of 

 mercury passes into red with disengagement of heat. If a body 

 has been transformed from one state into another by heat, it 

 stops in it, and on cooling does not again absorb heat. 



Many phenomena which have hitherto been ascribed to greater 

 or less chemical affinity, the author thinks he can explain by his 

 theorem of mechanical energy. Thus sulphuric acid is not a 

 stronger acid than hydrochloric because it forms a precipitate in 

 chloride of barium and expels hydrochloric acid. A solid body 

 is here formed under disengagement of heat. In nature a ten- 

 dency prevails to transform chemical work into heat ; and that 

 may be the cause of the formation of a solid body. 



M. Becquerel has published* a series of researches on the 

 chemical effects produced in capillary spaces. The following 

 account of them has been taken, with occasional abridgment, 

 from a paper by Professor De la Rive in the Bibliotheque Univer- 

 selle de Geneve. 



M. BecquerePs first series of experiments were executed by 

 means of a slightly cracked tube. The cracks are made by tra- 

 cing one or two longitudinal lines with a diamond on the surface 

 of the tube, and then applying in any part of these lines the 



* Comptes Uendus, May 13, June 17? and November 4, 186/ ; and 

 January 13 and April 20, 1868. 



