On Elas^ticifi/. !4l 



slowly, sometimes more rapidly, and sometimes one of the 

 forces may come to nothing and then return back to the 

 same kind without passing to the other. And Jm- all this, 

 it seems, there is full roovt in the distances that are in- 

 sensible to us, seeing the least part of space is divisible 

 in injlnitum. 



Assuming all this, and exhibiting a curve and other ne- 

 cessary appendages to assist the mind in comprehending his 

 theory, the author applies it to explain all the phnenomena 

 of the material universe, assuming also in his progress such 

 forms and arrangements as are required to make the system 

 applv to the properties possessed by matter in those modi- 

 fications which distinguish and divide it into classes : thus 

 solid bodies are formed of parallclopipidcs, fibres, and of ir- 

 regular fi^i^n•eg, occasioning a greater cohesion than in fluids, 

 and preventing the motion of the parts round one another; 

 so that when one part is moved the rest follow. Those 

 bodies whose particles are placed in limits which have strong 

 repulsive arches within them are harder ; those are softer 

 whose particles have those arches of repulsion weaker. 

 When the particles are placed in limits that have weak 

 arches of repulsion and attraction on each side, the body is 

 flexible; aad, if those arches are short, the particles may 

 come to new limits of cohesion, and remain bent: but if 

 the arches are longer the repulsion and attraction may act, 

 and restore the body to its former position ; nav, in doing 

 this with an accelerated velocity, the parts will pass their 

 former limits, and then vibrating backwards and forwards 

 exhibit that eflcct which is called elasticitv. 



On this theory we shall only observe, that whatever con- 

 viction it may carry to minds habituated to profound ma- 

 thematical investigations, it can convey but little informa- 

 tion to a man who merely aims at a knowledge of the pro- 

 perties of matter, as consisting, not of inexiended atoujs, 

 but of such molcculoc as occupy sensible space. What the 

 wiser is such a man ibr being told that certain forces exist, 

 and that some idea may be formed of their mode of ope- 

 rating by conceiving them to act in the directions of certain 

 curves, and with powers varyino" according to circumstaneos? 

 He may absent to this ; but as his weak mind can conceive 

 nothing of matter inextended, either in itself or in its atoms, 

 he cannot consider liis difficulties as solved bv merely hav- 

 ing them stated to him in anew form; for to him the whole 

 of this system appears to l)e no more at best but a regular 

 mathematical statement of those operations of matter, the 

 causes of which he still wishes to explore. 



C. BarrucI 



