152 Mr. S. T. Preston on the Continuance of 



the smallest portion of any increase, must fall upon the part 

 A B ; and this we in fact learn from the above consideration. 

 That I have therein taken no account of the action of neigh- 

 bouring current-threads makes no difference ; for the result 

 of this action is, for A B exactly as for B 0, that the mole- 

 cular magnets are brought into a position a little nearer the 

 perpendicular to the plane of the plate. 



In Beetz's experiment the iron-wire spiral to be magnetized 

 was inside the magnetizing copper spiral, so that the turns of 

 the one were parallel to those of the other. Consequently 

 the molecules were more or less approximately so placed that 

 (supposing the windings horizontal and the current flowing 

 in the copper in the direction of motion of the hands of a 

 watch) all the north poles pointed downward.. The principal 

 current, on the other hand, called forth a circular magnetizing; 

 therefore in the portions of wire belonging to the front half 

 of the iron spiral, although the principal current flowed in the 

 direction in which the hands of a watch move, the north poles 

 in the anterior semicylinders into wlr'ch each portion of the 

 wire can be resolved were directed more or less upward, in the 

 posterior (inner) downward. Conversely, in the portions of 

 wire of the hinder half-spiral, the north poles in the posterior 

 (outer) semicylinders were directed upward, and downward 

 in the anterior ones. If, then, the magnetizing force of the 

 principal current is not very little in comparison with the 

 other, half of the current-threads present a stronger resistance 

 than before the transverse magnetizing, the other half a weaker 

 one ; thus the total resistance remains nearly unaltered. The 

 negative result of Beetz's experiment is therefore not sur- 

 prising. 



[To be continued.] 



XIX. On the Possibility of accounting for the Continuance of 

 Recurring Changes in the Universe, consistently with the 

 Tendency to Temperature-Equilibrium. By i5. Tolver 

 Preston*. 



THE idea of the ultimate final cessation of all activity and 

 life in the universe has been contemplated by many phy- 

 sicists with some dissatisfaction, and with the desire, if possible, 

 to find some explanation or physical means by which so appa- 

 rently purposeless an end is averted, and of avoiding the ne- 

 cessity for assuming in past time a violation of physical prin- 

 ciples at present recognized to exist. The allied notion of an 

 unstable universe whose parts tend to agglomerate together into 

 one mass by successively falling together, would certainly, to 

 * Communicated by the Author. 



