360 Mr. D. Vaughan on the Solar Spots 



meeting of the British Association for the Advancement of 

 Science, I alluded to the influence of large planets in altering 

 the amount of luciferous tether supplied to suns, and thus causing 

 a periodical occurrence of spots on our own luminary, and far 

 more decided changes in the hrilliancy of many of the stars. On 

 comparing my theoretical conclusions with the results of obser- 

 vations on the variable stars, the coincidence appears so satisfac- 

 tory that I again venture to call attention to the subject. 



The action of gravity must cause the fether of space to increase 

 its density, not only on the surfaces of suns and planets, but 

 also along the regions through which they have taken their rapid 

 course. To prove this, it is only necessary to investigate the 

 movements of an immense number of bodies not larger than 

 cannon-balls ; if they were scattered over an extensive tract of 

 space, and were travelling in parallel paths with the same velo- 

 city, until they came within the range of the sun's attraction. 

 It will be readily seen, that the several planes in which each of 

 these bodies are urged by the solar power, must have a common 

 intersection in a line coinciding with the direction of their pri- 

 mitive motion. If our sun should travel through a region 

 occupied by a similar assemblage of bodies which had previously 

 been at rest, he would compel each of them to describe hyper- 

 bolic oi'bits, all intersecting the line of his progressive motion ; 

 and the space along this line would be most densely populated 

 by the transient masses. Now the influence of elasticity would 

 prevent the particles of the interplanetary medium from descri- 

 bing similar orbits ; but it could not change the planes of their 

 motion, nor prevent all from intersecting the same line. The 

 region from which the sun departs will accordingly be the focus 

 to which the sether must press from all surrounding space; and 

 here it will be concentrated in the greatest quantity, having its 

 density much augmented by the conflict of opposing currents of 

 enormous extent, and moving with an immense velocity. 



Nor must it be supposed that the great elasticity of the 

 setherial particles will render the augmentation of density incon- 

 siderable. The pressure of an atmosphei'ie column, about 40 

 miles high, makes the air we breathe several thousand times 

 more dense than it would be if the height of the atmosphere 

 were only one thousand feet above the level of the sea. Though 

 the modulus of elasticity should be many million times as great 

 in the luciferous sether as in our common air, we must recollect 

 that it has to contend with the weight and inertia of a far more 

 extensive mass of the rare fluid. The pressure of a column, 

 whose height is commensurate with the range of solar attraction, 

 must increase to a considerable extent the density of the rether ; 

 while the repulsion of its particles would require years to restore 



