LAUGEL'S PROBLEMS OF NATURE AND LIFE. 335 



great poem deserves to be read in its relation to more 

 than one of the doctrines of our own day. 1 



We might almost mention among new modes of 

 analysis, were it not that the products evade examina- 

 tion, those beautiful experiments of Tyndall in which 

 he decomposes highly attenuated vaporous compounds 

 by the solar or electric beam, passed through the tubes 

 containing them. The delicate aerial clouds gradually 

 developed in these tubes, while they illustrate the 

 exquisite atomic tenuity of matter, suggest analogies 

 or explanations of other physical phenomena occurring 

 in our atmosphere, as well as remotely in the universe 

 around us. 



Before quitting the atomic theory we must briefly 

 notice the remarkable conclusions drawn from the 

 theory of gases by Sir W. Thomson and Clarke Max- 

 well, as to the minuteness of the molecules composing 

 them a minuteness of which a hundred-millionth 

 part of a centimetre is but an approximate expression. 

 More recently, again, Sir W. Thomson has denoted 

 what he considers evidence of fixed physical limits to 

 the smallness of atoms and molecules one very in- 

 geniously derived from the contact electricity of metals 

 others drawn from the theories of capillary attraction, 

 and from that of gaseous actions ; severally affording 



1 Speaking thus of Lucretius, we are tempted to transcribe a few lines 

 we have not seen quoted in reference to the topic, now so much dis- 

 cussed, of the early condition of man, and the order in which he succes- 

 sively fashioned weapons and implements to his use : 



1 Arma antiqua, manus, ungues, dentesque fuerunt ; 

 Et Lapides, et item sylvarum fragmina rami. 

 Posterius Ferri vis est, ^Erisque reperta. 

 Sed prior JEris erat quatn Ferri cognitus usus.' 



