1833.] Attraction and Repulsion. 447 
creased in the direct ratio of the increase of the bulk.—Thus one cu- 
bic inch of air will need the absolute elastic power of each particle to 
be increased eight times, in order to expand it to 8 inches. The bulk 
having been increased eight-fold, the distance of the particles will be 
doubled (i. e. as the cube root of the bulk); on doubling their distance 
their elastic force is halved, i. e. from 8 it has become 4, and at the 
same time the pressure is increased as the square of their distance 2, 
and is therefore 4. Here then the elasticity and pressure balance each 
other, and the particles will be stationary. Hence the power endow- 
ing the particles with mutual elasticity must have been increased in the 
same ratio as the increase of the bulk. If these 480 degrees of tems 
perature can double the bulk of a given volume of gas, they must 
double the whole absolute quantity of heat in the gas. The specific 
heat of the gas at 512° will be double that of the pint at 32° in the 
experiment. Now this is a point which probably no one acquainted 
with all that is known regarding caloric will maintain. We can hard+ 
ly suppose that the whole specific heat of a gas at 32° (viz. that due to 
its capacity and temperature, and all the latent heat due to its gaseous 
state) is equal only to that introduced by the 480 degrees. Analogy 
would teach us, that it is, at least, three or four times as much. If 
then the 480 degrees of heat can effect as muchexpansion as the whole 
previously contained in the gas could, we are led necessarily to the 
conclusion that the latter is opposed, even in gaseous matter, by an at- 
traction, so far as to have an effective repulsive force equal only to that 
subsequently introduced by 480 degrees of temperature, nay to much 
less, for the fact of the presence of this attraction being once establish- 
ed, between the gaseous particles, this force must be considered as 
operating against the heat subsequently introduced ; and must lessen 
its effective power. | 
|_This argument I may illustrate in a more familiar manner. Let a cy- 
lindrical. vessel half filled with any gas, nitrogen, stand inverted ina 
vessel of water, so that the liquid being on a level within and without 
the pressure on the gas shall be just that of the atmosphere. If the 
surface be two square inches, this will be equal to thirty pounds. Let 
an equal quantity of oxygen gas be added, and suppose it at first to re- 
main under the nitrogen, and the vessel to be raised so as to preserve 
the same level in the water. The oxygen will now bear the whole pres- 
sure, and communicate the same to the nitrogen aboveit. Each will 
be pressed on with a force of 30 pounds. In the course of time, how- 
ever, the two gases will become completely mixed. Each will occupy 
the whole vessel, the bulk of each being doubled ; but the two together 
