2fi(> VARIATIONS OF SPECIFIC GRAVITY. 



These experiments have hitely been continued in Basel by my col- 

 lea erne, and he finds that glowed i)latinuni wire 0.4 nnn. in diameter 

 of specific gravity 21.4olT fell oft' in density to 21.4133 when drawn 

 to 0.1 mm., and on being heated white hot again rose to 21.4346. Wires 

 of chemically pure platinum, an alloy of platinum with 10 per cent 

 iridium, aluminum, and copper all behave in a similar manner, and 

 rolled aluminum foil and hammered zinc plates as well. 



A change of electrical conductivity had previously been noted after 

 incandescence in cold-drawn wires of platinum, platinum-iridium, 

 aluminum, and copper. 



These researches will be continued in all the directions here indi- 

 cated, and an attempt ^^ill be made to measure the alterations by the 

 volumetric method. 



