390 SCIENCE IN SHORT CHAPTERS. 



dilation. At 61 miles above the earth's surface there must 

 be atmospheric matter of sufficient density to offer to the 

 passage of this meteor through it an amount of resistance 

 which produced an intense white heat, visible by its lumi- 

 nosity in broad daylight. 



In the above-quoted paper, read by Mr. Joule before the 

 Manchester Literary and Philosophical Society on Decem- 

 ber 1, 1863, he refers to subsequent observations and esti- 

 mates 116 miles as "the elevation at which meteors in 

 general are first observed" i.e., where our atmosphere is 

 sufficiently dense to generate a white-heat by the resistance 

 it offers to the rapidly flying meteor. 



It is curious to observe how, in dealing with actual phys- 

 ical facts, a mathematician of the solid practical character 

 of Joule becomes compelled to practically throw overboard 

 the orthodox theory of limited atmospheric extension. 

 Here, in making his calculations of the resistance of at- 

 mospheric matter at this elevation, be bases them on the 

 assumption of a decrease of density at the rate of "one 

 quarter for every seven miles," and indicates no limit at 

 which this rate shall vary. Very simple arithmetic is suffi- 

 cient to show that this leads us to the unlimited atmos- 

 pheric extension, for which I have contended we may go 

 on for ever taking off a quarter at every seven miles, and 

 there will still remain the three quarters of the quantity 

 upon which we last operated, or, more practically stated, 

 we shall thus go on seven after seven until we reach the 

 boundaries of the atmospheric grasp of the gravitation of 

 some other sphere. 



Surely the time has arrived for the full reconsideration 

 of this fundamental question of whether the universe is 

 filled with atmospheric matter or is the vacuum of the mo- 

 lecular mathematicians plus the imaginary "ether," which 

 has been invented by its mathematical creators only to ex- 

 tricate them from the absurd dilemma into which they are 

 plunged when they attempt to explain the transmission of 

 light and heat by undulations traveling through space 

 containing nothing to undulate. 



They have filled it with immaterial matter evolved en- 

 tirely from their own consciousness, which they have gra- 



