6 



SCIENCE 



[N. S. Vol. XXVII. No. 679 



series of lectures on "Molecular Dynamics 

 and the Wave Theory of Light," before a 

 very unusual auditory from both sides of 

 the ocean. These lectures, first published 

 twenty years later, were eharaeteristieally 

 Thomsouian, and represented his long at- 

 tempt to make the elastic theory of the 

 ether work successfully. Constructing a 

 model of a molecule by means of concen- 

 tric hollow shells with springs between to 

 give many modes of vibration, he was led 

 to an explanation of anomalous dispersion, 

 without knowing of its experimental dis- 

 covery by Kundt and Christiansen, or its - 

 explanation by Helmholtz ten years before. 

 This ignoring of the work of others was 

 characteristic of both Thomson and Helm- 

 holtz, and perhaps constitutes the strength 

 of great thinkers. Possibly in this way is 

 to be explained Thomson's cold attitude 

 toward the electromagnetic theory of light, 

 which he maintained until after the world 

 in general was convinced of its truth. He 

 was determined at all hazards to make the 

 elastic ether do, probably beeavise he saw 

 that even if light is to be explained as 

 electromagnetic waves, we have still to give 

 a dynamical explanation of electricity and 

 magnetism. Of late years the pendulum 

 has swung the other way, and there is now 

 an attempt to explain all dynamics on an 

 electromagnetic basis, but with this Lord 

 Kelvin would probably have had no sym- 

 pathy. In these Baltimore lectures we 

 find a remarkable description of a probable 

 way to make electric waves, which was 

 almost exactly realized by the method of 

 Hertz three years later, coupled with the 

 erroneous opinion, from which Thomson 

 could hardly rid himself, that they would 

 be waves of compression, and would travel 

 much faster than light. In order to ex- 

 plain elasticity, he had a penchant for the 

 ideas of Father Boscovich, of forces ema- 

 nating from centers, from which he built 

 up atoms, ether, and even made applicatiori 



to radioactivity. One of his last papers 

 is on a " Plan of an Atom to be capable of 

 storing an Blectrion with Enormous 

 Energy for Radioactivity," and in a paper 

 with the characteristic title of "^pinus 

 Atomized" he put forth the model of an 

 atom consisting of a globe of positive elec- 

 tricity permeated by a multitude of minute 

 negative electrions, as he persisted in call- 

 ing them, ignoring the general use of the 

 word electron. 



Lord Kelvin devoted a considerable por- 

 tion of his energies to tilting at windmills 

 and championing lost causes. Of this his 

 treatment of the elastic and electric 

 theories is an example. Another bete 

 noire in late years was the Maxwell-Boltz- 

 mann theorem of the partition of energy, 

 which he characterized as a cloud upon the 

 kinetic theory of gases. The writer once 

 enjoyed the good fortune of spending 

 several days in the company of Lord Kel- 

 vin, and of hearing him frequently train- 

 ing his guns on that target. At last he 

 plucked up courage to ask, "Lord Kelvin, 

 what do you consider to be the funda- 

 mental error in the argument of Maxwell 

 and Boltzmann?" "I don't think there is 

 a single thing about it that is right," was 

 the instant comprehensive answer, to which 

 there appeared no obvious reply. 



Lord Kelvin's personality was a most at- 

 tractive and original one. To see him and 

 hear him talk was to be lost in admiration 

 of his vigor, his quickness and his enthu- 

 siasm. Nothing was lost to him, and he 

 was never idle. In the railway carriage 

 on the return to London on the occasion 

 mentioned he soon pulled out his note-book, 

 and was figuring on the ether flowing 

 through an atom, the result of which figur- 

 ing was apparent the week after at the 

 Paris congress. Helmholtz, on a visit to 

 Thomson on his yacht, the Lalla Rookh, 

 writes to his wife, after admiring the skill 

 with which Thomson managed the yacht, 



