On Radiant Matter. 29 



How long, think you, would it take for this small vessel to 

 get full of air ? An hour ? A day ? A year ? A century ? 

 Nay, almost an eternity ! A time so enormous that ima- 

 gination itself cannot grasp the reality. Supposing this 

 exhausted glass bulb, indued with indestructibility, had 

 been pierced at the birth of the solar system ; supposing 

 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 cycles 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 formation 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 have admitted its full quadrillion 

 of molecules.! 



But what will you say if I tell you that all these molecules, 

 this quadrillion of molecules, will enter through the micro- 

 scopic hole before you leave this room ? The hole being 

 unaltered in size, the number of molecules undiminished, 

 this apparent paradox can only be explained by again sup- 

 posing the size of the molecules to be diminished almost 

 infinitely so that instead of entering at the rate of 

 100 millions every second, they troop in at a rate of some- 

 thing like 300 trillions 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 possible duration of the Sun from formation to extinction has been 

 variously estimated by different authorities, at from 18 million years to 

 400 million years. For the purpose of this illustration I have taken the high- 

 est estimate. 



f According to Mr. Johnstone Stoney (Phil. Mag., vol. 36. p. 141), i c.c. of 

 air contains about 1000,000000,000000,000000 molecules. Therefore a bulb 

 13-5 centims. diameter contains J-3'5 3 x 0^5236 x 1000,000000,000000,000000 or 

 1,288252 350000,000000,000000 molecules of air at the ordinary pressure. 

 Therefore the bulb when exhausted to the millionth of an atmosphere contains 

 1,288252,350000,000000 molecules, leaving 1,288251,061747,650000,000000 

 molecules to enter through the perforation. At the rate of 100,000000 mole- 

 cules a second, the time required for them all to enter will be 

 12882,510617,476500 seconds, or 

 214,708510,291275 minutes, or 

 3-57 8 475 I 7 I 5 21 hours, or 

 149103,132147 days, or 

 408 501731 years. 



