200 DESCRIPTION OF A NEW CALORIMETER. 



merely observe,. that when we consider the quantity of calo- 

 ric unavoidably carried off, the coming so near an exact 

 mean «t the end of one minute is very surprising. 

 Dr. Crawford I will now endeavour to demonstrate by direct experi- 



mistaken, and men t s , that an increase of capacity does invariably take place 



his data erro- . . . P , 



neous. in a just raUo to the increase of temperature; and in the 



second place, that a mean, or an approximation to it, may 

 result as well from a gradual increase of capacity, as from 

 a permanency : consequently, that Dr. Crawford's experi- 

 ments and mathematical propositions are founded on false 

 data. 



Experiment ivhich proves the progressive Increase of Capa- 

 city. 



Experiment to The calorimeter being at the precise temperature of 48°, 

 which was also that of the room, I filled the interior com- 

 partment, No. 1, with water from a boiling kettle at 212°, 

 and having closed it as before represented with a thermome- 

 tric cork, I agitated the apparatus well for about the space 

 of lj minute, in a horizontal position, when the two ther- 

 mometers indicated 97°. Therefore the water at 212° had 

 lost 115°, which, being communicated to the water at 48° 

 in the second compartment, had raised its temperature 49 

 degrees. Having taken down these numbers, I poured out 

 the water from the interior compartment, and brought the 

 s calorimeter to the exact temperature of 150°, and again 

 filled the interior compartment with water from the kettle 

 at 212°; when, after brisk agitation as before, I found the 

 temperature to be 166°. Therefore in this experiment the 

 water at 212° had lost 46 degrees, which, being communi- 

 cated to the water in the second compartment at 15Q°, 

 raised its temperature but 16 degrees; whereas if equal in- 

 crements of caloric produced equal increments of tempera- 

 ture, or in other words if the capacity were permanent, it 

 should have raised it 19tt°t> which is easily demonstrated by 

 the following calculation. 



If 115 degrees raise water 49 degrees, what should 4G 

 raise it ? — Answer, 19rW' 



Here it is obvious, that the difference between lG and 

 19rrV> is the difference between the capacity of water at 48° 



and 



