SPECULATIVE SCIENCE. i 55 



direct vision, which is more thoroughly established than this. It ex- 

 plains with the utmost simplicity, and without introducing any but the 

 best-known properties of molecules, a great number of diverse phenom- 

 ena seemingly incapable of explanation in any other icay." Now, it 

 is a great pity that these glad tidings did not reach Professor Clerk 

 Maxwell before he was laid to rest in his early grave. They would 

 certainly have been a great comfort to him, and possibly might have 

 prolonged his life. For there is reason to suspect that in his latter 

 days he arrived at conclusions respecting the kinetic theory of gases 

 which bear a strange resemblance to my own. Being, not a scientific 

 dogmatist, but an honest and candid investigator in search of truth, he 

 came to see with ever-increasing clearness that the difficulties of his 

 favorite theory beset not only its fundamental assumptions, but also 

 their inevitable consequences, especially in their bearings upon the 

 theory of heat. After the appearance of Watson's treatise already 

 adverted to, on the 26th day of July, 1877, he published in "Nature" 

 (vol. xvi, No. 404) a review of it, in which he considered the signifi- 

 cance of Mr. Watson's propositions in connection with certain matters 

 discussed on pages 97, 99, and 127 of my book. And thereupon he 

 made this declaration (" Nature," vol. xvi, p. 245) : 



The clear way in which Mr. Watson has demonstrated these propositions 

 leaves us no escape from the terrible generality of his results. Some of these, no 

 doubt, are very satisfactory to us in our present state of opinion about the con- 

 stitution of bodies, but there are others which are likely to startle us out of our 

 complacency, and perhaps ultimately to drive us out of all the hypotheses in 

 tchich hitherto we have found refuge into that state of conscious ignorance which 

 is the prelude to every real advance in knowledge. 



I hope, by-the-way, that this last remark of the great scientist will 

 be pondered by those who complain that, after demolishing, as they 

 imagine, all current physical theories, I leave them in the midst of ruins, 

 and do not at once present them with a golden key for unlocking all 

 the mysteries of the universe, or, like Puck, in " Midsummer-Night's 

 Dream," " put a [theoretical] girdle round about the earth in forty 

 minutes." 



Before I leave this subject, I take the liberty of quoting another 

 passage from the same article, which Professor Newcomb, if he knows 

 anything about the discussions to which the kinetic theory of gases 

 has given rise, will find instructive. Speaking of Boltzmann's attempt 

 to reconcile the elasticity of atoms with their rigidity by increasing 

 their co-efficients of elasticity ad infinitum, so as to make them practi- 

 cally rigid a supposition also developed in an essay of Hugo Fritsch 

 in Konigsberg, entitled " Stoss zweier Massen unter der Yorausset- 

 zung ihrer Undurchdringlichkeit behandelt," which does not seem to 

 have fallen under Professor Maxwell's notice (and, I may add, a sup- 

 position of which Professor Newconib's "insuperable force" may 



