4 DH. F. HORTON ON THE EFFECTS OF CHANGES OF TKMPKRA ri i;l 



projecting flanges made of thick copper, and the two are screwed up tightly together 

 by 8 screws, a sheet of thin asbestos cardboard being placed l>etween. The internal 

 measurements of the box are 7 inches square by 5 inches deep, and the thickness 



Fig. 1. 



between the two walls is atxmt 1 inch. In the centre of the door is a small window 

 of optically worked glass through which the mirrors used in the timing arrangements 

 are viewed. 



To the upper end of the inner copper tube of the cylindrical part of the heater the 

 brass collar C is screwed, and in this works the brass head D, through the centre of 

 which passes the ^-inch steel rod E, the lower end of which is made into a clamp to 

 hold the wire. This clamp is shown on a larger scale in fig. 2, and was made in the 

 following manner. The end of the rod was turned down about inch and a steel 

 collar made to fit it. About f inch from the end the groove H was made perpendicular 



