Dr. II. T. I', //// 



"On the Capacity for Heat of Water between the Free/in^ and 

 I'xiilin^ Points, together with a Determination of the 

 Mechanical Equivalent of Heat in Terms of the International 

 Electrical Units. Experiments by the Continuous-flow 

 Method of Calorimetry performed in the Macdonald Physical 

 Laboratory of McGill University, Montreal." By HOWAIID 

 TUKNEK BAHXES, M.A.Sc., D.Sc., Joule Student. Communi- 

 cated by Professor H. L. CALI.KNDAK, F.RS. Received June 

 15, Read June 21, 1900. 



(Abstract.) 



At the Toronto meeting of the British Association in 1897, a new 

 method of calorimetry was proposed by Professor Callendar and the 

 author for the determination of the specific heat of a, liquid in terms 

 of the international electrical units. At the Dover meeting in 

 September, 1899, some of the general results obtained with the 

 method for water over a part of the range l>etween and 100 

 were communicated, with a general discussion of the l>earing of the 

 experiments to the work of other observers. In the present paper 

 the author gives a summary of the complete work, in the case of water, 

 to determine the thermal capacity at different temperatures between 

 the freezing and boiling points. 



Theory of the HetJiod. 



If a continuous flow of liquid in a tube be made to carry off a con- 

 tinuously supplied quantity of heat EC, in electrical units, then after 

 nil temperature conditions have become steady 



JsQ (0i - ) t + (0! - 0) ht = ECt 

 where 



J = mechanical equivalent of heat, 

 Q = flow of liquid per second, 

 s = the specific heat of the liquid, 



00 = the temperature of the liquid flowing into the tube, 



01 = the temperature of the liquid flowing out of the tube, 



h = the heat loss per degree rise of temperature from the liquid 



flowing through, 

 t = the time of flow. 



In the case of water, E represents the E.M.F. across an electrical 

 heating conductor in the tube, and C the current flowing. In this 

 case, which is treated of entirely in the present paper, Jx is replaced 



