Temperature on the Specific Heat of Aniline. 49 



lator could again heat the inflow. As now arranged, when 

 working above temperatures about 20° C. a small motor acts 

 as a heart and, the tap-water being shut off, pumps the tank- 

 water itself round through the silver tube placed above the 

 gas-jets. The water, by passing through the pump &c, is 

 slightly cooled : thus the work of the regulator is confined to 

 simply supplying the heat lost by convection, radiation, &c, 

 and it performs this task admirably. As an illustration, I 

 may mention that in the series of over 50 experiments treated 

 of in this communication on only one occasion did the tem- 

 perature of the steel chamber change by as much as j^-q C. 

 throughout the duration of an experiment. On the solitary 

 occasion that a change amounting to nearly ^q° 0. was 

 observed, the cause was found in the caking of the lime through 

 which the gas was passed on its way to the regulator, and, in 

 consequence, the experiment was discarded before working- 

 out its results. 



A large screw, placed in the tank-water, revolved at about 

 800 times per minute and raised a considerable sea — the flow 

 passing round, under, and over the steel chamber, the top of 

 which was about 4 in. beneath the surface of the water. 



The calorimeter was formed of brass and was suspended by 

 glass tubes which, after passing through the lid of the steel 

 chamber and through the water, projected above the lid of 

 the tank. The diameter and depth were each about 10 centims. 

 and the capacity about 700 cubic centims. Within it was sus- 

 pended a silver flask with which three silver tubes communi- 

 cated. One was connected with a glass tube passing to the 

 exterior through which substances could be introduced. The 

 second tube, which was about 18 feet in length, was, after 

 leaving the top of the flask, twisted into a spiral within the 

 calorimeter ; the other end, terminating in the lid of the 

 calorimeter, was then connected by a glass tube with a four- 

 way tap entirely immersed in the outer tank. The third tube, 

 which opened into the bottom of the flask, communicated with 

 about 30 feet of copper tubing placed in the tank-water. The 

 object of the whole arrangement was that the gas on leaving 

 the calorimeter (after evaporating any liquid in the flask) 

 should have acquired the temperature of the calorimeter, and 

 that any gas passed into the flask should assume the tempera- 

 ture of the outer tank.- True, this portion of the apparatus 

 was not necessary to the experiments on aniline, but I have 

 felt it advisable to describe it, as explaining some of the sub- 

 sequent operations. 



A coil of fine german-silver wire, supported on glass pillars, 

 was placed within the calorimeter and so arranged as to 



Phil. Mag. S. 5. Yol. 39. No. 236. Jan. 1895. E 



