Chemistry and Physics. 405 
sage of these bodies, it is concluded that very little energy is 
needed to-effect any separation of ether particles which may take 
place, and the greatest possible dilatation of this ether must be 
much smaller than is the case with glass or water. In comparing 
authorities, Herr Glan finds that taking the greatest possible dila- 
tation of glass before disruption at +z, the value of n=, which 
is twice the value taken by Thomson. For the greatest possible 
dilatation of water under the same conditions, the value of g+.455 
is taken, This gives the value n= zz), if the dilatation of the 
ether before disruption is as great as in the case of water. This 
The unit of work taken is that which will lift one cubic centimeter 
of water one meter high. This unit is 1000 kilogrammeters. The 
Sceurred at the early age 
und Chemie, No. 8, 1879, p. 584. aR 
11. Units and Physical Constants; by Professor J. D. Evererr. 
Second edition. It appears, however, in a much enlarged form, 
ae Se ee he ferred t iform series 
- .& the many physical constants referred to a un 
of fundamental oe can hardly be over-estimated, and hence the 
Sreat value of Professor Everett’s book, in which this end is 
plished, 
