latter 

 leasure 



SCIENTIFIC SIDE-LIGHTS 



according to law. This grand conception, 

 which is sketched in the " Discours,'] and 

 more fully developed in the " Principes " 

 and in the " Traite" de rHomme," he worked 

 out with extraordinary power and knowl- 

 edge ; and with the effect of arriving, in the 

 last-named essay, at that purely mechanical 

 view of vital phenomena towards which 

 modern physiology is striving. HUXLEY 

 Lay Sermons, serm. 14, p. 331. (G. P. P., 

 1899.) 



2115. MATTER, ATOMIC CONSTI- 

 TUTION OF Hypothesis of Centers of Force 

 Phenomena Not So Explained. Accord- 

 ing to this celebrated hypothesis [the cor- 

 puscular hypothesis of Boscovich], a portion 

 of matter consists of an assemblage in space 

 of an indefinite number of points kept at a 

 given distance by attracting and repelling 

 forces: these points have relative position, 

 but not magnitude, and are merely centers 

 of action of the forces which affect our 

 senses, and since all our knowledge of mat- 

 ter is derived from the action of these forces, 

 to infer that these points are anything more 

 than the centers of forces is going beyond 

 our premises. 



This hypothesis readily explains the 

 statical properties of bodies, such as elas- 

 ticity, porosity, impenetrability, solidity, 

 liquidity, crystallization, resistance to com- 

 pression when a force is applied to either 

 side of the body, etc.; but it fails to ac- 

 count for the dynamic phenomena of masses 

 of matter, or those which are referable to 

 the three laws of motion. It is not there- 

 fore enough that we assume, as the elements 

 of matter, an assemblage of points in space 

 from which merely emanate attracting and 

 repelling forces ; we must also suppose these 

 points to be endowed with inertia, or a 

 tendency to resist a change of state, whether 

 of rest or motion, and a tendency to move 

 in a straight line ; also to possess the prop- 

 erty of preserving the effects of a number of 

 impulses, as well as that of transforming 

 motion from one point to another, the one 

 losing as much motion as the other gains. 

 But the admission of the existence of points 

 with such qualities brings us back to the 

 Newtonian hypothesis of matter. HENRY 

 The Atomic Constitution of Matter, Scien- 

 tific Writings, vol. i, p. 256. (Sm. Inst., 

 1886.) 



2116. Hypothesis of New- 

 ton One Kind of Matter throughout All 

 Space Its Four States The Imponder- 

 ables Ether Cannot Exhibit Weight. We 

 may assume, with Newton, the existence of 

 one kind of matter diffused throughout all 

 space, and existing in four states, namely, 

 the ethereal, the aeriform, the liquid, arid 

 the solid. This method of presenting the 

 atomic hypothesis of the constitution of 

 matter may at first sight appear startling; 

 but on a little reflection it will be found a 

 necessary consequence of the attempt to ex- 

 plain the mechanical phenomena of matter 

 by an assemblage of separate atoms. It may 



be objected to the assumption of one kind of 

 matter that the fact of the imponderable 

 nature of light, heat, electricity, and mag- 

 netism require at least two kinds of matter ; 

 but if we adopt the theory of undulation, 

 the phenomena of the " imponderables " ( as 

 they are called) are merely the results of 

 the motions of the atoms of the ethereal 

 medium combined in some cases with the 

 motion of the atoms of the body; and since 

 the vibrations of the atoms of a mass of 

 matter do not increase the attraction of the 

 earth on the mass, an increase of tempera- 

 ture in a body cannot change its weight; 

 and also because the ethereal medium fills 

 all space, a portion of this medium can no 

 more exhibit weight than a quantity of air 

 when weighed in the midst of the atmos- 

 phere. HENRY Atomic Constitution of Mat- 

 ter, Scientific Writings, vol. i, p. 257. ( Sm. 

 Inst.; 1886.) 



2117. Materiality of Atoms 



The Ether a Form of Matter, Filling All 

 Space. According to the view we have 

 given, a portion of matter consists of an 

 assemblage of indivisible and indestructible 

 atoms endowed with attracting and repel- 

 ling forces, and with the property of obedi- 

 ence to the three laws of motion [viz.: 

 inertia, coexistence of separate motions, 

 and equality of action and reaction]. All 

 the other properties, and indeed all the 

 mechanical phenomena of matter, so far as 

 they have been analyzed, are probably ref- 

 erable to the action of such atoms, ar- 

 ranged in groups of different orders, . . . 

 the distance in all cases between any two 

 atoms being much greater than the diam- 

 eter of the atoms or molecules. We are 

 obliged to assume the existence of an ethe- 

 real medium formed of atoms, which are 

 endowed with precisely the same properties 

 as those we have assigned to common mat- 

 ter; and this assumption leads us to the 

 inference that matter is diffused through all 

 space. 



That something exists between us and the 

 sun, possessing the properties of matter, 

 may be inferred from the simple fact that 

 time is required for the transmission of 

 light and heat through the intervening space. 

 . . . That the phenomena of light and 

 heat from the sun are not the effect of the 

 transmission of mere force (without inter- 

 vening matter), such as that of attraction 

 and repulsion, is evident from the fact that 

 these [latter] actions require no perceptible 

 time for their transmission to the most dis- 

 tant parts of the solar system. If the sun 

 were to be at once annihilated, the planet 

 Neptune would at the same instant begin to 

 move in a tangent to its present orbit. 

 HENRY The Atomic Constitution of Matter, 

 Scientific Writings, vol. i, p. 257. (Sm. 

 Inst., 1886.) 



2118. MATTER IN SPACE AND IN 

 TIME "There are only two different as- 

 pects," says Dr. Thomas Brown, " in which 

 matter can be viewed. We may consider it 



