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XXI. Researches on the Specific Heats, Densities, and Expansions 

 of some Liquids. By C. Marignac*. 



Part I. Specific Heats. 



W7" HEN narrating, in a previous memoir f, some prelimi- 



* ▼ nary researches upon the part played by water in saline 

 double decompositions, and its influence on the thermal effects 

 which accompany them, I noticed some apparently very singular 

 facts, but could not yet regard them as certain, since in my 

 calculations I had not taken account of the specific heats of the 

 solutions employed. 



Intending subsequently to resume their examination by more 

 rigorous methods, I undertook a series of researches on the spe- 

 cific heats of the solutions. I was not then aware that M. 

 Thomsen had been for some time engaged in a work of the same 

 kind and had nearly brought it to a conclusion. He has just 

 announced that the results of his observations (of which he has 

 already given a summaryj) will shortly be published. 



Although this publication almost renders unnecessary the 

 continuation of my w T ork, and mine are still far from being so 

 comprehensive as M. Thomsen^s researches, I wish to state the 

 results at which I had already arrived ; for several of the com- 

 pounds on which I have been occupied have been likewise the 

 subject of his experiments, and it will not be uninteresting to 

 compare results which, obtained by very different methods, will 

 show, if one may judge from those he has already published, a 

 very satisfactory accordance. I have also examined some solu- 

 tions to which, perhaps, he has not turned his attention, and 

 which will lead me to add some general observations to those 

 which he has already presented. 



For the determination of the specific heats of aqueous solu- 

 tions, I have used one of the most simple and well-known me- 

 thods : it consists in measuring the rise of temperature produced 

 in an ascertained weight of liquid by the introduction of a 

 heated body. 



Two objections have been made to this method, impugning its 

 accuracy. 



The first is founded on the difficulty of knowing exactly the 

 temperature of the body which is immersed in the liquid, or 

 rather (for I shall show, further on, that in operating as I have 



* Translated from the Archives des Sciences Physiques et Naturelles for 

 November 1870. 



t Arch, des Sci. Phys. et Nat. vol. xxxvi. p. 319. 



X Berichte der Deutschen chemischen Gesellschaft zu Berlin, 1870,p. 716 ; 

 and Archives, vol. xxxix. p. 153. 



