342 ME. W. S. TUCKER ON HEATS OP 



The following specific heats were obtained for hydrochloric acid :- 



The above table shows that at about air temperatures very little change occurs in 

 the specific heat of concentrated hydrochloric acid solutions. 



Even allowing for possible errors of experiment there is evidence of a minimum 

 value whose position lies between 5 C. and 15 C. 



The above results are consistent with those previously obtained at an average 

 temperature of 9'92 C. Thus for concentration 2375 the specific heat by inter- 

 polation is 0'583 ; for concentration 14'9 the value is 0'648 ; and for concentration 

 10'44 it is 0711. 



The values employed in the subjoined table of heats of dilution were derived from 

 the above tabulated values by interpolation. 



The process of equalisation of temperatures before mixing water with the solution 

 was performed as nearly as possible before the pipette was immersed in the solution. 

 After immersion the pipette was left for some hours and the solution was continuously 

 stirred by the propeller stirrer, driven at a high speed. 



The process of mixing of water and solution was allowed five minutes to complete, 

 and during this interval the radiation correction was applied. It was always found 

 that after that period the temperature changes were always those which would be 

 foretold by the previous radiation experiments. 



