174 On a Modification of JBunsen's Calorimeter. 



are allowed to fall to the bottom of the tube, they sink partly 

 into the mercury, and quickly give up their heat to it, so 

 that it is more nearly the same as if the mercury had been 

 heated. 



3. A large-sized box is employed, in which plenty of ice is 

 placed, so as to completely surround the instrument. 



4. As the mercury sometimes moves very sluggishly, gentle 

 tapping, not vertically, but horizontally, has been found very 

 beneficial. 



We will now take an example to illustrate the method of 

 working : — 0*396 grin, of mercury was weighed out and 

 allowed to remain for some time in contact with the bulb of a 

 thermometer. Meantime the instrument was gently tapped 

 and the height read. The mercury was then poured in after 

 the thermometer-reading (18°* 6 0.) had been taken. The 

 rise obtained on the scale was 15. An experiment with iron 

 was then made ; and since the specific heat of iron is about four 

 times as great as that of mercury, '144 grin., or about one 

 fourth the weight of the mercury, was taken. The tempera- 

 ture was still 18°' 6 ; and the maximum rise obtained was 18 ; 



. * . specific heat of iron ='0333 x t^ x ttj ='110. 

 1 15 144 



The following results have been obtained : — 



Substance. 



Weight. 



Tempe- 

 rature. 



Kise. 



Specific heat. 

 Hg=-0333. 



f Mercury 



•364 



•148 



16-8 

 171 



15 



32 



•174 



\ Sulphur 





f Mercury 



•325 

 •144 

 •134 



16-2 

 16-3 

 16'2 



10 

 15 



22 



•110 



•178 



i Iron , 



[ Sulphur 





f Mercury 



•396 

 •144 

 •081 



18-6 

 18-6 

 18.6 



15 



18 

 16 



•110 

 •174 



< Iron 



(Sulphur 





Mercury 



•400 

 •144 

 •083 



18-0 

 18-0 

 180 



14-5 

 18-0 

 15-5 



•115 

 •175 





Sulphur 







•505 

 •145 

 •118 



15-8 

 16-2 

 16-2 



14-5 

 13-5 

 17-0 



•112 

 •177 





Sulphur 







Mean specific heat, iron -1118 



, sulphur '1756 



True. 



•1138 

 1776 



