28 



therefore electricity was made use of. Four incandescent 

 lamps E in copper tubes F in the water-jaclcet under 

 the inner chamber were connected to the laboratory main. 

 Only one of thèse four lamps is shown in the figure. The 

 régulation of température also took place by means of 

 electricity. The thermoregulator K (cf. flg. 4 and the spécial 

 description) consisted of an open thermometer with a large 

 mercury-reservoir and a wide capillary in which a platinum- 

 wire could be pushed up and down; this wire made contact 

 with the rising mercury when the température had risen 

 to the desired point. 



This regulator (cf. plate I) was connected to a couple 

 of accumulators, a resistance-box and a switch, which 

 automatically interrupted the electric current of the lamps 

 as soon as the température and with it the mercury 

 had risen sufficiently to close the circuit through the 

 accumulators. The accuracy of this apparatus left nothing 

 to be desired. The mercury of the regulator rose 6 

 m. m. for a rise of température of one degree C, and 

 so it was quite easy to adjust by hand the platinum 

 wire so that the température remained constant to 0.1° C. 

 In order to open the thermostat it was necessary to 

 lower the level of the water about 5 cm. so that the 

 lid C of the inner chamber became visible. To prevent 

 a loss of beat the water was run into a second vessel 

 by means of a wide tube G, entering the outer vessel 

 near the bottom. The latter could be moved up and down 

 by means of two pulleys in the ceiling. which made the 

 water flow up or down; it was constructed on the prin- 

 ciple of a hay-box, which made the loss of beat only very 

 small. As the outlet was wide and the round lid (which 

 took up a little more than half the top wall of the inner 

 vessel) was fastened with six nuts only, the opening and 

 closing took only a few minutes; hence* the fall of tem- 



