Force and Form. 1049 



ture are probably those of the 27th to the 29th octaves, far below the 

 visible octave. I conjecture, that at these low temperatures the imme- 

 diate subdivisions of the solid body are not molecules but aggregations 

 much larger than molecules, composed in fact of man}^ molecules held 

 together by cohesion. These aggregations may be called moles ; a term 

 meaning masses. These moles then are of great variety in size and 

 shape, and they generally maintain their organization up to the tem- 

 perature of white heat. At red heat temperature those of them that 

 happen to possess the proper fundamental pitch vibrate in the red tones, 

 that is waves of the lower end of the 44th octave ; or rather they vi- 

 brate at such rates as to communicate such motion to their ethereal 

 spheres. When the body is subjected to the temperature of white heat 

 all the moles set up vibrations in their ether, and the result is the radi- 

 ation of light in all the wave lengths of the 44th octave. When the 

 temperature is raised above this some of the moles are resolved into 

 their constituent molecules, and this process increasing with increasing 

 temperature, the variety of these aggregations is constantly lessened, 

 the spectrum showing discontinuity as thej T are broken up. 



It would seem reasonable to suppose that if all the particles in a 

 body were of the same size and form, their activities would give rise to 

 the same sort of radiation, that is light of the same color. That it 

 does not, is proof of a difference in their modes of activity, and this in 

 turn may be accounted for by the hypothesis of the moles in various 

 shapes and sizes. The different states of a body under the different 

 temperatures may be considered as quasi allotropic, isomeric, or poly- 

 meric, (pp. 348351). But even in the gaseous state and incandescent, 

 every body still emits waves in different lengths, and so marks lines on 

 the spectrum in various numbers from four in hydrogen to many hun- 

 dreds in iron. The spectrum of nitrogen is changed completely by 

 change of temperature at high degrees, and this has been explained by 

 supposing nitrogen to be liable to various allotropic states. ( Roscoe. ) 

 This has also been found to be the case with other gases. Another ex- 

 tremely important fact is that gases when greatty condensed give con- 

 tinuous spectra. When hydrogen was placed by Lock}^er in a vessel 

 connected with an air pump, and then some of it pumped out so as to 

 make the residue rarer, its lines across the spectrum became narrower. 

 On the other hand when more hydrogen was pumped into the vessel so 

 as to make it more dense, the lines began to widen, and continued to 

 widen as the pressure was increased, until finally they touched each 

 other, forming a continuous spectrum. ( The ordinary spectrum of hy- 

 drogen consists of four bright lines, one very bright red line, one bright 

 greenish-blue line, one dark blue or indigo, and one violet line that 

 only comes out when the temperature is high. See table p. 383). In 



