1904.] 



GOODWIN ELECTROLYTIC CALCIUM. 



389 



lime formed smothers the flame. When sent whizzing through the 

 air against asbestos, bricks or cement it burns violently with a 

 brilliant white light like magnesium and leaves a streak like anti- 

 mony. It is not hardened by heating red hot and plunging into 

 water. At 3oo°-4oo°C. it is as soft as lead and the irregular sticks 

 can be easily hammered on an anvil, rolled, swaged or worked into 

 any shape whatever by simply heating from time to time. When 

 cold a bright calcium surface becomes dull rapidly in ordinary air, 

 but if hot the metal can be brightened with a file or polished in the 

 lathe with emery cloth and will remain bright as long as it is hot. 

 About 300 grams of fine bright specimens were prepared as follows : 

 A glass cylinder and its stopper were put in an air bath, gradually 





Figure 8. 



heated and kept at 150° C. The calcium was kept hot on a stove 

 plate and the pieces polished one at a time and put in the cyhnder 

 in the air bath where they kept bright till all were polished. A 

 little paraffin was rubbed around the stopper and the ^cylinder 

 closed. In this dry air they have lost none of their lustre and their 

 bright surfaces are as distinctly metallic as any other metal. Fig. 

 8 shows the cylinders of crystals and solid metal and a six-inch 

 stick of polished calcium. 



Specific Gravity. 

 The density of oil was determined by the density bottle and from 

 weighings of a bright piece of calcium in air, and in this oil its 



PROC. AMER. PHILOS, SOC. XLIII. 178. Z. PRINTED JAN. 3, 1905. 



