DESCRIPTION OF A NEW CALORIMETER. ] 97 



VI. 



Description of a newly .invented Calorimeter; with Experi- 

 ments to prove, that an increased Capacity, for Caloric 

 accompanies an Incrcafe of Temperature. By Joseph 

 Ueade, M. D. 



SIR, Edinburgh, Jan. 22, 1808. 



I- 

 Beg leave to communicate, through the medium of your 



very interesjt'mg an( I scientific Journal, the invention of a 



calorimeter, - r ree from those inaccuracies incident to the ap- Defects of the 



paratus of Messrs. Lavoisier and Laplace, in which it was apparatus of 

 : .: '. , . . . r ... LavuLbier and 



impossible to guard against errours arising from capiw^ify^ , Laplace. 



attraction, from the process of freezing and thawing pro- 

 ceeding at the same period, and likewise from, the influence 

 of a current of atmospheric air. In this communication I 

 will confine myself to a summary description of the appa- 

 ratus, and of a discovery deduced from it, which must in- 

 fluence in a most important manner, if proved, the investi- 

 gations of caloric ; that, contrary to received opinion, water Capacity of 

 increases in capacity from the thermometric range of 32 t° r i? increas/s 

 212, in a just rate for every degree of temperature commu- uniformly with 

 nieated. its tem P era " 



Dcscription of the Calorimetbr, ichich is to be formed of thin 

 sheets of Brass or Tin. 



The innermost compartment No. 1, PI. V, tig. 1,- designed T-te catoriinfc* 

 for the fluid to be subjected to experiment, is to be stopped CT 

 with a thermometric cork, a, or, what is better, a thermo- 

 meter surrounded with chamois leather, and made to fit 

 accurately the aperture. The second compartment, No. 2, 

 holds a quantity of water, and is likewise to be stopped by 

 a thermometric cork, b, made air-tight by sealing wax, as 

 this water is not to be removed from the compartment during 

 the course of the experiments. 



The external compartment, 3, is designed to act as an 

 imperfect conductor of caloric, and is to have a coating of 



list 



