26~ REPORT 1861. 



dane career, not by a single dilapidation of its planetary structure, but by a limited 

 number of paroxysmal convulsions, each burling forth an immense quantity of 

 matter, witb peculiarly farom-able conditions for sweeping close to the central 

 sphere, and forming a host of blazing meteors to encu'cle his suiface. 



Investigations on the effect of the departing mass in causing instability by its 

 attraction, and of the opposite tendency of the expansion of the orbit, have led me 



to estimate the amount separated by each catasti'ophe at — ^ / -— , V denoting the 



volume of the satellite, A its longest semidiameter, and C a constant, which may 

 be taken 8000 in case of a homogeneous fluid, but somewhat less when the body is 

 soUd. The influence of the opposing forces in limiting the range of the great rup- 

 tiu-e wUl diminish the loss which this expression woidd assign to a very large dis- 

 membei-ing body. From the relative magnitudes of the eaith and the moon, and 

 the relation observed between the members of physically double stars, it would not 

 be imreasonable to expect that central spheres 200,000 or 300,000 miles in dia- 

 meter may have worlds capable of exhibiting, diu^ing their last stage of existence, 

 a few himdi'ed of these temfic scenes, and sending forth on many of them more 

 meteorites than could be fonned from our entire globe. Of the periods inter^'ening 

 between each, no precise estimate can be given, but it must doubtless comprise 

 many centimes. On the first of these awful events, the meteoric light must be 

 confined to the vicinity of the plane in which the attendant moved, and from which 

 the fragments can deviate little ; but these will soon form a ring aroimd the primary, 

 and make the luciferous action disappear. The mass launched forth on every sub- 

 sequent paroxysm must move with terrific speed through the annular field of dis- 

 connected matter, scattering it in every dii-ection, and causing it to extend the me- 

 teoric exhibitions over a much greater part of the surface of the central orb. 



The pressm-e imparted to a fluid by a moving body is proportional to the cube of 

 the velocity, though the resistance to motion, being equal to the difference of the 

 pressiu-e on two opposite sides, varies according to a different law. Now, if attrac- 

 tion causes the space-pervading ether to become more dense in the \"icinity of the 

 earth's sm-face, the excess of density must be increased almost a thousand-fold by 

 the pressure of a meteorite passing through this ethereal atmosphere with the 

 greatest velocity with which a body moving in an ellipse around the sim can ap- 

 proach the earth. Regarding meteors as luminous in consequence of this compai'i- 

 son, it is evident that they must display their light with the utmost splendour, and 

 at the greatest elevations, on large spheres which exert the most powerful attrac- 

 tion on their surfaces. From the imperfect accounts which I have seen of Mr. 

 Hamngton's observations on September 1st, 18o0, 1 have concluded that the meteors 

 which he saw falling to the solar disc must have been self-limiinoiis about one 

 hundi'ed thousand miles above the boimdaiy of the great ocean of flame, \^^len 

 we consider the extraordinaiy brilliancy often attending the descent of these bodies 

 to the eai-th, and reject the extravagant idea of gigantic meteorites supposed to 

 escape into space after grazing or striking om- atmosphere, we find additional proofs 

 of the existence of dormant photospheres ai'ound obsciu'e celestial orbs, and of the 

 relation between objects so disproportionate in size as a shooting and a temporary 

 star. 



Physics. 



(hi tlie Application of the Principle of tlie Consen^ation of Force to the mechanical 

 explanation of the Correlation of Forces. By J. S. Stuaet Glexkie, M.A. 



The author's chief object was to show that the principle of the conservation 

 of force, with the facts of the correlation of forces, reqidred a new or modified con- 

 ception of matter. The piinciple of the conseiTation of force might be thus ex- 

 pressed : every motion is resisted, and produces a new motion, deteimined by the 

 conditions of such resistance. To this principle the conception of matter, as made 

 •up of hard inelastic particles in an elastic ether, seemed to be opposed. Matter was 

 ■rather to be conceived as made up of molecules, exerting mechanical pressure on 



