44 W. Thompson on the size of Atoms. 
make of a combination of the results of Clausius and Maxwell. 
Having defined the radius of a gaseous molecule, I call the 
double of the radius the diameter; and fe volume of a globe 
of the same radius or diameter I call the volume of the 
molecule. 
Sri experiments of Cagniard de la Tour, papers spagnanlty 
o Andrew s, on the condensation of gases 
ule; and the number of m 
volume cannot pose 25, 000, 000 PEERS i 
the volume of a globe whose radius is that average length of 
path. Taking now the preceding estimate, y;J555 of a centi- 
meter, for the average length of path from collison to collision, 
we conclude that the diameter of the gaseous molecule cannot 
be less than s,55¢s555 Of a centimeter; nor the number of 
molecules in a cubic centimeter of the gas (at  OPHIDArY, density) 
greater than 6 x 107? (or six thousand millio 
undred ite: Miok ‘million miton million) From this tit we 
assume for a moment a cubic arrangement of molecules), the 
distance from center to nearest center in solids and liquids may 
be estimated at from zsshs005 a t0 gynaeaae0 Of a centimeter. 
lead all to substantially the same estimate of the jee of 
molecular structure. Jointly they establish with what we can-* 
not but regard as a very high degree of probability the con- 
clusion that, in any ordinary Ti uid, transparent solid, or seem- 
ingly opaque solid, the mean distance between the centers of 
contiguous molecules is less than: the hundred- millionth, and 
greater than the two thousand-millionth of a centimeter. 
To form some conception of the degree of coarse-grainedness 
indicated by this none BsiN, imagine a rain drop, or a globe of 
glass as large as a pea, to be magnified up to the size of the 
earth, each. tons raps 4 being magnified in the same 
proportion. The magnified structure would be coarser grained 
than a heap of small shot, but probably less coarse grained than 
a heap of cricket-balls. 
