228 KINETIC THEORIES OP GRAVITATION. 



attracted as it wore, to the origin of vibration, with a range of influ- 

 ence approximately proportional to tLe area of the disk. The same 

 phenomenon was observed with the employment of a bell, when caused 

 to sound by drawing a bow across its edge, excepting that at the nodes 

 of oscillation no " attraction" was exhibited.* 



In an essay entitled "A synthetic Glance at the Forms and Forces of 

 Matter,'' published in 1801, the same author, recapitulating his views 

 and observations of 1S3U and 1835, and still maintaining that all the 

 properties of bodies are derivatives of their translatory or vibratory 

 movements, and that the equilibrium and the phenomena of the world exist 

 only under the condition of constant pressure of the incoercible aether 

 upon coercible matter, aud the reaction of the latter upon the former, 

 argues that, " if it be shown that the vibration of the atoms of bodies 

 may and actually does cause a rarefaction in the sphere of activity of 

 each of the atoms," this constitutes a proof that " the approximation of 

 the atoms of bodies of ponderable matter is due to the rarefaction of 

 the imponderable fluid, and consequently to the diminution cf its press- 

 ure in the space between the atoms of the same body j " aud hence that 

 " we are compelled to admit that attraction is a mechanical force, con- 

 sisting, first, of the rarefaction of the aether between molecules, masses, 

 or the heavenly bodies, resulting from the ceaseless vibration of the 

 atoms of ponderable matter, and secondly, of the reaction from the 

 exterior pressure of the aether upon the same, resulting from the general 

 pressure of the imponderable universal medium which constitutes the 

 mother-liquor of the world."! 



In this article the writer brings out very distinctly an idea first sug- 

 gested by Newton, and which has recently been fermenting, so to speak, 

 in the minds of various speculative writers, to wit, that matter as ex- 

 perimentally cognizable by our senses — having for its lowest constituent 

 unit the compounded molecule of uniform structure for each element- 

 ary substance, the indivisible " atom " of the chemist — has been by 

 some mysterious process evolved in the indefinite past from the struc- 

 tureless impalpable aether filling immensity. That the ultimate mole- 

 cule of matter as known to us is a highly complex or organized cosmos, 

 appears to be sufficiently demonstrated by the definite multiple peri- 

 odicities exhibited by gaseous spectra. If the sympathetic responses 



*De8 mouvementa de Voir et des pressions de Vair en mouvement. (8vo, Paris, 1835.^ 

 Sir Henry C. Englefield, in 1773, observed at Brussels, that during the ringing of ;i 

 large church bell, (weighing 1G,000 pounds,) the aerial vibrations affected a mercurial 

 barometer, which was placed experimentally about seven feet below it, by raising 

 the column about one-hundredth of an inch. (Journal of R. I., vol. i, p. 157.) On 

 which Dr. Young oilers the following suggestion : " It is easy to suppose that the law 

 of the bell's vibration was in this experiment such that the air advanced toward the 

 barometer with a greater velocity than it receded, although for a shorter time ; and 

 that hence the whole effect was the same as if the mean pressure of the air had been 

 increased." (Lectures on Natural Philosophy, 1H07, 2 vols, quarto, vol. ii, p. 270.) 



\Presse Scientifique, 1861, vol. iii, p. 130. 



