[SHAW] 



A SENSITIVE BATH-THERMOSTAT 



131 



cleaned thin glass tubing approximately one and a half centimetres 

 diameter, should be bent into the form of a plane worm grid occupying 

 a square of about 42 cms. side with spaces of about 3 cms. between 

 bends. One end is closed later, and the other which is bent round 

 with an elbow below the plane of the rest of the grid, must be turned 

 up and joined to the portion illustrated in the diagram. The grid is 



Vertical End of Thermoregulator. 



filled with about 1,100 cubic centimetres of toluene reaching partly 

 into the elbow, the remainder containing mercury. The object of 

 the elbow is to prevent the toluene coming up into the vertical part. 

 In the figure, F represents the vertical end from the grid, fused 

 on to an ordinary glass three-way tap or stopcock, B, with arms of 

 about 1-5 mm. diameter. This is fused to another three-way tap, 

 D, at the side as shown, and in the upper arm from B a bulb, C, of 



