THE CALORIMETER. 



53 



The ebonite cover to the copper cylinder F, pierced with suitable holes, 

 was now screwed to brass ledges soldered to the inner wall of the cylinder, 

 2 cm. below its rim. The cracks were stuffed with tissue paper. F was then 

 lowered into an empty thermostat, of capacity about 80 liters, and a tube 

 delivering a rapid stream of pure dry carbon dioxide was fitted into its 

 proper hole in the cover. The outlet for the tube gas was exactly in the 



F 



Fig. 9. Portions of the Apparatus for Measuring the Heat of Dilution. 



center of the cover and contained a wire attached to the partition at H ; the 

 wire passed through a small greased rubber tube fitted with a pinchcock, 

 while the gas escaped through a sideneck. When all air was displaced, a 

 weighed amount of the amalgam to be diluted was run into the empty half 

 of C from a separating funnel filled with carbon dioxide. A Beckmann ther- 

 mometer was then lowered into the hole, and clamped firmly in place, its 

 bulb half way between the surface and the bottom of the amalgam. All 

 the tubes leading into the calorimeter were also clamped, after which the 

 tenth of a liter of a mixture of hard and soft paraffin melting at about 45 

 Centigrade were poured upon the ebonite cover. This, when hard, made the 

 vessel F water-tight ; but as an additional precaution a small outward pres- 

 sure of carbon dioxide was always maintained by closing all outlets. The 

 thermostat was now filled well above the top of F, and regulated by a very 

 large and sensitive electric cut-off. The make and break was in an arti- 



