360 



REPORT 1864. 



The wires were pressed at a gentle heat, the press being carefully bored and 

 cleaned beforehand. As the wire came from the press it was received on a 

 smooth board. It was then at once soldered on to the connexions and placed 

 m the trough. The solder employed was AVood's cadmium alloy. After 

 being cut from the connectors the wii"e was straiglitened by rolling between 

 two boards with great care ; it was then placed on the board beneath the 

 beam-compass, adjusted to the groove below the line of motion of the cross 

 wires of the telescope, and carefully measured and then weighed. 



Wire No. I. was cut from a bar of commercially pure lead, prepared by 

 Mr. Baker of Sheffield. 



Wire No. II. made from lead obtained by heating the acetate thrice re- 

 crystallized. This specimen was kindly prepared by Mr. Mathews. 



Wire No. III. from the acetate of lead of commerce twice crystallized. 



Wire No. IV. from the acetate of lead of commerce three times crystallized. 



AVire No. V. from the seventh recrystaUization of acetate of lead. Kindly 

 prepared by Professor Atkinson. 



