[ 241 3 



L. Netv Outlines of Chemical PhUosophi/. %Ez.WALKER,E.5g. 

 of Lynn, Norfolk. 



[Continued from vol. xlvii. p. 9'.] 



M 



De Luc has favoured the philosophical world with a new 

 instrument, wliich he calls The Electric Column. The effects of 

 this instrument are very wonderfr.l; for, if we look upon it merely 

 as a philosophical toy, it excites our astonishment nearly as much 

 as eitlier maguetisrn, electricity, or galvanism did, when they 

 were first discovered : hut when the electric column is used as 

 a philosophical instrument, it may tend to enlarge the bounds of 

 chemical philosophy; for it has happened, and not unfrequently, 

 that improvements in science were at a stand, until some new 

 improvement was made in the arts. 



V/hen we investigate the properties of physical elements, 

 which produce such an infinite variety of physical effects, we 

 should be verv circumspect in our operations, and not content 

 ourselves with'a single experiment, wliich may seem to support a 

 favourite hvpothesis, but vary our experiments ; and if a great 

 iir.mber of them, made with appropriate instruments, prove the 

 truth of the same hypothesis, that hypothesis may be deemed a 

 theorv, and used as such in all our future investigations. 



The only means we have of investigating physical causes, is 

 bv experiment and observation ; for physical certainty does not 

 admit of mathematical demonstration ; it is entirely obtained by 

 our senses. We see the sun, and feel his effects, — we view the 

 moon and all her various changes; but the existence of those 

 objects cannot be mathematically demonstrated : all the know- 

 ledge we have of their existence is wholly derived from om- senses. 

 Hence all our experimental knowledge comes under the deno- 

 mination oi physical cerlainty. 



" In ascending from effects to causes we must ever arrive, 

 upon whatever hypothesis we proceed, at some first cause, which 

 does not admit an explanation from mechanical principles*." 



Now the first causes or elements, by which the various phse- 

 nomena in nature are produced, are three ; that is to say, gra- 

 vitv, magnetism, and electricity: — gravity is a simple element, 

 but the other two are compounds. Each pole of a magnetic bar 

 contains a different clement. In two bars homogeneous poles 

 repel, and heterogeneous poles attract each other. And the same 

 law obtains in electricity; for, what have been called positive 

 and negative electricity are two distinct elements ; — electrical 



• W.'itison's Cliemical Kssays, vol. i. p.»163. 

 Vol. 48. No. 222. Ocl. 181(J. Q elements 



