Proceedings. 



ioi 



meters can be conveniently tested at the same time. The 

 apparatus consists essentially of two cylindrical vessels, one 

 being placed inside the other. Both are filled with water. 

 The thermometers are placed in a carrier inside the inner 

 vessel. The water in the outer vessel is maintained at any 

 desired temperature by an electric current passing through 

 a platinum wire in the water. The water in the inner vessel 

 is kept stirred by means of a revolving screw turned by an 

 electric motor. 



" The details of the different parts are shewn in (Figs. I 

 to 3). Fig. 1 shews the carrier made of brass which holds 



Fig. 1. 



Fig. 2. 



the thermometers. They are all kept in place by an india- 

 rubber band pressing them against strips of brass bent so as 

 to form a triangular groove. Fig. 2 shews the inner 

 vessel round which a framework is fixed, carrying platinum 

 wire. This wire is insulated from the vessel by means of 

 indiarubber tubing which is placed over the brass supports. 

 Fig. 3 shews the whole apparatus when put together. 

 The brass rod passing into the vessel carries a pulley at one 

 end and a stirrer at the other. 



"The thermometers are compared at three temperatures, 

 viz., 98 , 103 , 108 . The vessel, without the carrier, having 

 G 



