BOSCOVICH. 



Boscovich. Philosophise Naturalis thcoria redacta ad unicam 

 legem virium in natura existentium. Vienna:, 1758. 

 4to. The second edition of this work appeared at 

 Venice in 1762, and the third at Vienna in 1764. 



De Solis ac Lunse defectibus libri quinque. Lon- 

 don, 1760, 4to. This work was reprinted at Venice 

 in 1761 in 8vo. ; and a French translation of it by 

 the Abbe Barruel, appeared at Paris in 1779. 



Voyage Astronomique et Geographique pour me- 

 surer deux degres du meridien par les PP. Maire et 



749 



Hugon, et Boscovich. 



Boscovich, traduit du Latin, par le P 

 augmente par le P. Boscovich lui-meme. 



Memorie sulli cannochiali diottrici. Milan, 1771. 



Beside these works, Boscovich wrote several trea- 

 tises on practical hydraulics, connected with the sub- 

 ject' of rivers, harbours, and lakes. See Elogio del 

 Boscovich per il Sr. Baiamonti. Ragusa, 1789, 8vo. 

 Journal des Scavans, Feb. 1792, p. 113. Journal 

 de Paris, 13th Mars. 1787. (,3) 



BOSCOVICH'S THEORY. 



Boscovich's 

 theory of 

 Natural 

 Philoso- 

 phy. 



Introduc- 

 tory obser- 



The theory 

 of Bosco- 

 vich, a 

 mean be- 

 tween that 

 of Leibnitz 

 and New- 

 ton. 



X he theory of natural philosophy which claims 

 Boscovich for its author, has attracted, in no small 

 degree, the attention of the learned : And although 

 we are by no means disposed to imagine, that much 

 progress is likely to be made in physical science by 

 the original excogitation, or by the general applica- 

 tion of theories of any kind, and are rather inclined 

 to fall in with the opinion of the celebrated Bacon, 

 that mankind are much more liable to be seduced 

 into the winding mazes of error and fancy, than di- 

 rected in the more difficult path of truth and know- 

 ledge, by that fondness for systems, and those habits 

 of generalization, to which they are so much addict- 

 ed ; yet this theory has appeared so specious, so 

 general in its application, and so well adapted to the 

 explanation of most of the difficulties that occur ia 

 physical science, that we have thought it would be 

 proper to give our readers such an account of it, at 

 least, as, if not sufficient to render them masters of 

 the ingenious conceptions of its author, may per- 

 haps induce them to search for farther information, 

 in the works of the illustrious Ragusan. 



This theory is alleged, by Boscovich, to hold the 

 mean between those of Leibnitz and of Newton ; since 

 it admits, with the former, that the elementary par- 

 ticles of matter are simple and unextended ; and with 

 the latter, that they act on each other by mutual 

 forces, which are variable at different distances. 



We may add too, that, with Leibnitz and his fol- 

 lowers, Boscovich argues strenuously for the exist- 

 ence of the general law of continuity. While, with 

 the followers of Newton, he admits, in general, the 

 actio e distanti ; and also agrees with them in their 

 ideas respecting light, gravity, the pressure of fluids, 

 &c. 



But from the Leibnitzian this theory differs wide- 

 ly, in not admitting that continued extension can 

 arise from contiguous and inextended atoms ; a dif- 

 ficulty long ago urged against the system of Zeno : 

 and also, in alleging, that the ultimate particles of 

 matter are homogeneous, in opposition to the princi- 

 ples of indiscermbles, and the sufficient reason urged 

 against that doctrine by the disciples of Leibnitz. 



From Newton also he conceives himself to differ, 

 in explaining by one law of forces, not only all those 

 phenomena (and many more) for which the former 

 author, in his last optical query, 6eems to think three 

 principles were requisite, viz. gravitation, cohesion, 

 and fermentation ; but also in alleging, that, at the 

 ieast distances, the mutual forces are not attractive, 



3 



but repulsive ; and that this repulsive force, with 

 the diminution of distance, increases in infinitum. 

 Of course, it necessarily follows, that cohesion does 

 not arise from absolute contact of parts ; and that, 

 in fact, absolute mathematical contact, as it is called, 

 cannot possibly exist. 



Let us now proceed to unfold the theory. The 

 first elements of matter, according to Boscovich, are, 

 points altogether inextended and indivisible, dissemi- 

 nated in an immense vacuum, and placed at certain 

 distances asunder. These distances may be increased 

 or diminished, but cannot altogether vanish, without 

 an absolute compenetration of particles ; for their pos- 

 sible contiguity he altogether denies. These par- 

 ticles he conceives endued with inertia ; persever- 

 ing, if single, in their state of rest, or uniform recti- 

 lineal motion. 



He conceives two of these points of matter to have 

 a determination, at some distances, to approach each 

 other ; at others, to recede : and this he calls, the 

 force attractive or repulsive, the magnitude of which 

 changes with the distances, according to some law 

 which may be expressed by an algebraical formula, or, 

 as is common in mechanics, by a curve line. This law 

 of the forces is such, that, in the smallest distances, it 

 is repulsive, increasing indefinitely as the distance is 

 diminished ; and is therefore equal to the extinction 

 of any force of approach, however great. At a dis- 

 tance somewhat greater, this force diminishes, so 

 that a very little way off, it vanishes entirely : be- 

 yond that, the force becomes attractive, which, as 

 we continue to pass outward, arrives at its maximum, 

 then diminishes and vanishes ; after that, a repulsive 

 force takes place again, which, in its turn, increases 

 to a maximum, then diminishes and vanishes ; and 

 thus,' passing through several alternations until we 

 arrive, at length, at a force constantly attractive, 

 but diminishing inversely as the square of the dis- 

 tance, which continues at least as far as the limits 

 of our planetary system, and is no other than the ge- 

 neral law of Newtonian gravity. 



The apparent complication of this, will be best 

 removed, and a general idea of the whole system 

 most readily obtained, by referring to Figure 1. 

 Plate LXV. where the axis C AC has, in the peint A, 

 a perpendicular drawn to it ; on either side of which, 

 there are two equal and similar branches of a curve. 

 One of these, DEFGHIKLMNOPQRSTV, has, 

 in the first place, the asymptotic arc ED. That is, 

 if it were produced towards the parts BD, beyond 



Boscovich's 

 theory of 

 Natural 

 Philoso- 

 phy. 



The theory 

 expounded. 



By help oj 



a curve. 



Plate 

 LXV. 

 Fig. I. 



