198 DESCRIPTION OF A NEW CALORIMETER. 



list or flannel between the sheets of brass, which, combined 

 with the confined air. renders the instrument extremely accu- 

 rate, a minute elapsing before the thermometer fell 1 degree 

 at 150°. Therefore in experiments scarcely requiring that 

 time, there can be no abstraction of any consequence by 

 the atmosphere. 

 Method of When we wish to estimate the specific caloric of two 



comparative fluids, suppose oil and water, we bring the calorimeter to 

 specific heat of the precise temperature of 32°, 40°, 50°, or any other we 

 two fluids. d es i re> indicated by the two thermometers. We then fill 

 the interior compartment, No. 1, with water at 212°, and 

 immediately stop it with the therm ometric cork, a. After 

 agitating the apparatus for about the space of 1 J minute in 

 a horizontal position, the thermometers indicate the rise 

 experienced by the water at 50° in the second compart- 

 ment, and the number of degrees lost by the water at 212° 

 in the interior. Suppose the calorimeter be raised from 50° 

 to 80°, we take that number as the specific caloric of water. 

 We then pour the water from the interior compartment, 

 and again reduce the temperature of the apparatus to 50°, 

 which is speedily accomplished, by pouring cold water into 

 the innermost compartment, until the thermometers are re- 

 duced to the desired point. We are next to fill the interior 

 compartment with oil at 212°; and if, after agitation, on 

 examining the two thermometers, we find the temperature 

 raised, suppose to 60°, we easily find the specific caloric of 

 oil compared with water. T? .«s taking water as the stan- 

 dard, in a short time all fluids may be examined. By sub- 

 Solids and cor- stituting an iron cage, solids may be subjected to ex per i- 

 rosive fluids rnent; so likewise may fluids, which act chemically on metals, 

 bTexandned! b y enclosing them in a glass vessel. 



Th uth re - ' am at P resent engaged in a series of experiments, which 

 ga^- d in a se- I hope soon to be enabled to lay before the public. Here 

 s of expen j, ne rea( ] er j s to take notice, that I have only used ideal 

 numbers, more clearly to illustrate trie mode of operating 

 with the apparatus, and by no means indicative of the real 

 specific calouc of oil and water. I will end this part of my 

 communication by remarking, that in this instrument the 

 inaccuracies arising from abstraction of caloric by the at- 

 mosphere and vessel are obviated, which was impossible by 



means 



|N 



ments. 



