Voiv. 6, 1920 
PHYSICS: A. G. WEBSTER 
651 
+ 
T{v + ft 2 
a) = RT, 
(1) 
in the simplified form, suitable for the high temperatures concerned (2000 °— 
3000° C) 
p{v - rj) = RT (2) 
We shall use nearly the notation of Charbonnier and Sugot {Cours de 
Balistique, Imprimerie Nationale), but after having striven desperately 
with the multitude of engineers' units, pounds per square inch, kilograms 
per square centimeter or decimeter, inches or centimeters for bore and 
feet or meters for travel, and unknown units for velocity, acceleration and 
mass, we shall go back to first principle and express everything in C. G. S. 
23 
5^ 
absolute units. It should be an axiom that no formula should contain 
any (arabic) numeral quantities except natural constants of the universe 
such as TT, and that every formula should be correct in whatever system 
of units it is interpreted. It is hard to get engineers to agree to this. 
Consequently our unit of pressure shall be the dyne per square centimeter, 
with the convenience that a megadyne is between, and nearly equal to, 
the standard atmosphere and the kilogram per square centimeter at a 
place usually not specified, that 13 is the specific volume, in our units in 
cubic centimeters per gram or liters per kilogram, while T is the tempera- 
ture on the absolute scale, in our units centigrade degrees. If we con- 
sider a load of powder of mass co contained in a volume V, we define 
