W. Crookes—Radiant Matter. 261 
vacuum. The inrush of air impinges against the vanes and 
sets them rotating after the manner of a windmill. Let us 
suppose the molecules to be of such a size that at every second 
of time a hundred millions could enter. How long, think you, 
would it take for this small yessel to get full of air? An 
hour? A day? A year? A century? Nay, almost an 
eternity! A time so enormous that imagination itself cannot 
grasp the reality. Supposing this exhausted glass bulb, indued 
with indestructibility, had been pierced at the birth of the 
solar system ; mppeneg it to have been present when the 
earth was without form and void; supposing it to have borne 
witness to all the stupendous changes evolved during the full 
eycles of geologic time, to have seen the first living creature 
appear, and the last man disappear; supposing it to survive 
until the fulfilment of the mathematicians’ prediction that the 
sun, the source of energy, four million centuries from its forma- 
tion will ultimately become a burnt-out cinder ;* supposing all 
this,—at the rate of filling I have just described, 100 million 
molecules a second—this little bulb even then would scarcely 
apparent paradox can only be explained by again supposing 
the size of the molecules to be diminished almost infinitely— 
so that instead of entering at the rate of 100 millions ev 
second, they troop in at a rate of something like 300 millions 
a second. I have done the sum, but figures when they mount 
so high cease to have any meaning, and such calculations are 
as futile as trying to count the drops in the ocean. 
In studying this Fourth state of Matter we seem at length to 
have within our grasp and obedient to our control the little 
indivisible particles which with good warrant are supposed to 
has been 
ously estimated by different authorities, at from 18 million years to 400 million 
years. For the purpose of this illustration I have taken the highest estimate. 
_t According to Mr. Johnstone Stoney (Phil. : .c 
air contains about 1000,000000,000000,000000 molecules. Therefore a bulb 13°5 
centimeters diameter contains 13°5%x 0°5236 x 1000,000000,000000,000000 or 
1,288252,350000,000000,000000 molecules of air at the ordinary pressure. There- 
; e bulb whe u the million an atmosphere contains 
1,288252,350000,000000 molecules, leaving 1,288251,061747,650000,000000 mole- 
ion. At the rate of 100,000000 molecules a 
, the time required for them all to enter will 
12882,510617,476500 seconds, or 
214,708510,291275 minutes, Or 
3.578475, 171521 hours, or 
149103,132147 days, or 
408,501731 years. 
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