i879-] 
Molecular Physics in High Vacua. 
427 
In this other bulb is a remarkable collection of crys- 
tals of diamonds, which have been lent me by Professor 
Maskelyne. When I pass the discharge over them I am 
Fig. 10. 
afraid you will only be able to see a few points of light, but 
if you will examine them after the LeCture, you will see 
them phosphoresce with a most brilliant series of 
colours — blue, apricot, red, yellowish green, orange, and 
pale green. 
Next to the diamond the ruby is one of the most re- 
markable stones for phosphorescing. In this tube 
(Fig. n) is a collection of ruby pebbles, for the loan of 
VOL. ix. (n.s.) 2 F 
