1818.] M. Le Sage. 251 



to prove that all motion, of whatever kind, is merely a mode of 

 impulse. Of the existence of the communication of motion by 

 impulse, we have innumerable examples always before our eyes ; 

 we also see frequent instances of what we call attraction ; but it 

 is supposed that this latter is a more incomprehensible operation 

 than the former, and one with which we are less familiar and 

 less able to trace the steps by which it is produced. So far, 

 therefore, Le Sage's theory may be useful, and so far it seems to 

 advance us a step nearer to the ultimate object of all our re- 

 searches. 



It must, however, be acknowledged, that there are, on the 

 contrary, some considerations which lead us to doubt the utility 

 of all speculations of this kind. And, in the first place, it is a 

 circumstance of no small import to the makers of systems, that 

 no theory which proceeds upon the assumption of any imaginary 

 agent, like the gravific atoms of Le Sage, has ultimately kept its 

 ground, however ingenious they may have appeared, and what- 

 ever applause such speculations may have obtained from contem- 

 porary writers, they have ultimately fallen into oblivion, or have 

 only been remembered as appendages to the other productions 

 of their respective authors. So far indeed from adding to their 

 celebrity, they generally operate in the directly contrary manner, 

 they are tolerated rather than admired, and we view them with 

 regret, as a melancholy misapplication of labour and genius. 

 And, if we apply these reflections to the subject of our memoir, 

 when we consider what a large portion of his intellectual exist- 

 ence was spent in the construction of this system, when we 

 estimate the number of hours and days which he devoted to it, 

 and inquire what is the result, compared to what might have 

 been accomplished by the same expenditure of time and labour, 

 had he devoted them to the direct advancement of either mathe- 

 matical or experimental science, we cannot but regret the 

 choice which he made. It may be further observed that the 

 influence of such systems is often very unfavourable on the state 

 of science, at least on the minds of many of those who cultivate 

 it. They are too apt to mistake the nature of the advantage 

 which alone ought to be expected from these speculations : they 

 do not regard them as the means of acquiring knowledge; as 

 affording a commodious nomenclature, which may enable us to 

 express our ideas with greater clearness ; or as a species of alge- 

 braic notation, by which we may designate these ideas in a 

 precise manner, where, however, there is no natural resemblance 

 or relation between the idea and the mode of expressing it, but 

 they suppose them to be an actual detail of facts ; they reason 

 concerning the atoms, and ethers, and subtile fluids, as if they 

 were real existences, and build upon them a thousand whimsical 

 notions, which never entered into the contemplation of their ori- 

 ginal framers. We are therefore inclined to doubt whether any real 

 benefit would be conferred upon philosophy by any further eluci- 



