CONCLUDING REMARKS. 177 



else, say a steam-engine that is, by heat. This heat is pro- 

 duced by chemical affinity, i.e. the affinity of the carbon of the 

 coal for the oxygen of the air : this carbon and this oxygen 

 have been previously eliminated by the heat of the sun, or by 

 other actions difficult to trace, but of the pre-existence of 

 which we cannot doubt, and in which actions we should find 

 the conjoint and alternating effects of heat, light, chemical 

 affinity, &c. Thus, tracing any force backwards to its ante- 

 cedents, we are merged in an infinity of changing forms of 

 force ; at some point we lose it, not because it has been in 

 fact created at any definite point, but because it resolves 

 itself into so many contributing forces, that the evidence of 

 it is lost to our senses or powers of detection ; just as, in 

 following it forward into the effect it produces, it becomes, 

 as I have before stated, so subdivided and dissipated as to be 

 equally lost to our means of detection. 



Can we, indeed, suggest a proposition, definitely conceivable 

 by the mind, of force without antecedent force ? I cannot, 

 without calling for the interposition of creative power, any 

 more than I can conceive the sudden appearance of a mass of 

 matter come from nowhere, and formed from nothing. The 

 impossibility, humanly speaking, of creating or annihilating 

 matter, has long been admitted, though, perhaps, its distinct 

 reception in philosophy may be set down to the overthrow of 

 the doctrine of Phlogiston, and the reformation of chemistry 

 at the time of Lavoisier. The reasons for the admission of a 

 similar doctrine as to force appear to be equally strong. With 

 regard to matter, there are many cases in which we never 

 practically prove its cessation of existence, yet we do not the 

 less believe in it : who, for instance, can trace, so as to re- 

 weigh, the particles of iron worn off the tire of a carriage 

 wheel ? who can re-combine the particles of wax dissipated 

 and chemically changed in the burning of a candle? By 

 placing matter undergoing physical or chemical changes under 

 special limiting circumstances, we may, indeed, acquire evi- 

 dence of its continued existence, weight for weight and so 

 we may in some instances of force, as in definite electrolysis ; 

 indeed, the evidence we acquire of the continued existence of 

 matter is by the continued exertion of the force it exercises, 



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