THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



FEBRUARY 1864. 



XV. Speculative Ideas respecting the Constitution of Matter. 

 By T. Graham, F.R.S * 



IT is conceivable that the various kinds of matter, now recog- 

 nized as different elementary substances, may possess one 

 and the same ultimate or atomic molecule existing in different 

 conditions of movement. The essential unity of matter is an 

 hypothesis in harmony with the equal action of gravity upon all 

 bodies. We know the anxiety with which this point was inves- 

 tigated by Newton, and the care he took to ascertain that every 

 kind of substance, " metals, stones, woods, grain, salts, animal 

 substances, &c," are similarly accelerated in falling, and are 

 therefore equally heavy. 



In the condition of gas, matter is deprived of numerous and 

 varying properties with which it appears invested when in the 

 form of a liquid or solid. The gas exhibits only a few grand 

 and simple features. These again may all be dependent upon 

 atomic and molecular mobility. Let us imagine one kind of 

 substance only to exist, ponderable matter ; and further, that 

 matter is divisible into ultimate atoms, uniform in size and weight. 

 "We shall have one substance and a common atom. With the 

 atom at rest the uniformity of matter would be perfect. But 

 the atom possesses always more or less motion, due, it must be 

 assumed, to a primordial impulse. This motion gives rise to 

 volume. The more rapid the movement the greater the space 

 occupied by the atom, somewhat as the orbit of a planet widens 

 with the degree of projectile velocity. Matter is thus made to 

 differ only in being lighter or denser matter. The specific 



* From the Proceedings of the Royal Society, 1863, p. 620. Commu- 

 nicated by the Author. 



Phil. Mag. S. 4. Vol. 27. No. 180. Feb. 1864. G 



