606 Transactions of the American Institute. 



closed line of vortex core is literally indivisible by any action 

 resulting from vortex motion. If, then, we suppose all bodies to 

 be built up of vortex atoms, we give these atoms that infinitely 

 perennial specific quality " which philosophers commonly attribute 

 to atoms, by supposing them to be infinitely strong and infinitely 

 rigid. 



This latter "monstrous assumption," says Sir William, "has for 

 its only pretext, that urged by Lucretius, and adopted by Newton, 

 in which he has been followed by some of the most eminent modern 

 chemists and physicists, namely: that it seems to account for the 

 unalterable distinguishing qualities of different kinds of matter." 



But Helmholtz has proved this quality to exist in a perfect 

 fluid, when the motion, which he calls wirbel-bewegung, has been 

 created. Actual experiment confirms this result — that is, when 

 the smoke rings in air are so impelled as to come in collision, they 

 cannot be made to penetrate each other's volume, but rebound 

 with a certain resilience. Hence, Sir William concludes that they 

 fully answer all the requirements of gaseous atoms, under the dyna- 

 mical theory, and that, by packing them more closely, the proper- 

 ties of liquids and solids might be similarly accounted for, without 

 supposing the atoms themselves to be liquid or solid. 



Any diminution in the number of primary assumptions is obvi- 

 ously an important advantage gained for physical science; but I 

 imagine that this investigation of the vortex rings will be more 

 useful in elevating the ideas of philosophers out of the old grooves 

 of thought, enabling them to range more freely in hitherto untra- 

 veled paths, than the final establishment of a theory based upon so 

 complicated a fundamental idea. 



Few philosophers have done more than Sir William Thomson, 

 to advance the condition of modern ph3^sical science, and none are 

 better aware than he, of the inconsistencies and absurdities of the 

 old notions and hypotheses in relation to the molecular constitu- 

 tion of matter, which, however well they may have served to for- 

 mulate laws governing phenomena known at the time of their 

 inception, are entirely inadequate for that purpose in the existing 

 state of physical science. A remark by himself, on the subject, 

 will give a better idea of the anticipated value of this new hypo- 

 thesis, than any criticism can do in its present stage. He says: "A 

 magnificent display of smoke rings, which I recently had the 

 pleasure of witnessing in Professor Tait's lecture room, diminished 

 by one the number of assumptions required to explain the proper- 



