ON THE SOCIAL BENEFITS OF PARAFFIN. 65 



moon,, or otherwise freed from excess of atmospheric em- 

 barrassment. 



The recent experiments of Mr. Crookes, showing retarda- 

 tion of the radiometer with extreme exhaustion, seem to 

 indicate that heat-rays, like the electric discharge, demand 

 a certain amount of atmospheric matter as their carrier. 



I cannot conclude these hasty and imperfect notes, writ- 

 ten merely with suggestive intent, without quoting a pas- 

 sage from the preface to the " Correlation of Physical 

 Forces," which, though written so long ago, appeal's to me 

 worthy of the profoundest present consideration. 



" It appears to me that heat and light maybe considered 

 as affections; or, according to the undulatory theory, vibra- 

 tions of matter itself, and not of a distinct ethereal fluid 

 permeating it: these vibrations would be propagated just 

 as sound is propagated by vibrations of wood or as waves 

 by water. To my mind all the consequences of the undu- 

 latory theory flow as easily from this as from the hypothesis 

 of a specific ether; to suppose which, namely, to suppose 

 a fluid sui generis and of extreme tenuity penetrating solid 

 bodies, we must assume, first, the existence of the fluid it- 

 self; secondly, that bodies are without exception porous; 

 thirdly, that these pores communicate; fourthly, that mat- 

 ter is limited in expansibility. None of these difficulties 

 apply to the modification of this theory which I venture to 

 propose: and no other difficulty applies to it which does 

 not equally apply to the received hypothesis." 



ON THE SOCIAL BENEFITS OF PARAFFIN. 



To the inhabitants of Jupiter, who have always one, 

 two, or three of their four moons in active and efficient 

 radiation, or of Saturn displaying the broad luminous 

 oceans of his mighty rings in addition to the minor lamps 

 of his eight ever- changeful satellites, the relative merits of 

 rushlights, candles, lamps, and gaslights may be a question 

 of indifference; but to us, the residents of a planet which 



