42 
MR. J. J. WATERSTON ON THE PHYSICS OF MEDIA COMPOSED OF 
pendent of the indications of the barometer. This accords with the generally 
received theory. The molecular velocity of watery vapour being to that of air as 
\/1 4 - 4 to v9, the moisture in the atmosphere ought to have the effect of accelerating 
the velocity about 4 feet per second in temperate latitudes and 10 feet in the tropics 
at a maximum. 
Notes. 
Note A.—Motion Indestructible as Matter. 
The force of the descending weight is apparently expended, but it is only trans¬ 
ferred to the medium. If the elements of matter are perfectly elastic, this kind of 
transference must be of general occurrence wherever force is exerted, because the 
exertion of force is then but its transference either from its invisible constant 
condition, as in the medium, to its visible transitory condition, as in the ascent of the 
weight, or vice versd. In the former case force exists in the matter of the medium 
without change ; in the latter it is being transferred to the agent of gravitation, so to 
speak, and apparently released and disconnected from matter. The force of a medium, 
when it equilibrates a force of gravity, is similar to the force of a wind or a current of 
water on a stationary surface. Is it not possible to view all forces as inseparable 
from some form of matter, and all the phenomena of nature, as not consisting of the 
creation and annihilation of force, but in its transference from one form of matter to 
the other ? 
Note B .— Vapours. 
This enables us conveniently to represent the relation between the density and the 
square root of the mean square molecular velocity of a medium while it is being 
dilated or compressed. 
Fig. 3. 
'Take Q as the origin of co-ordinates, and let QP represent v and PN the /^/-. 
Join NQ. If the medium is compressed so that \/\^ becomes TS, then shall v 
become QT, and if it dilates so that becomes UW, then shall v become QU. 
