ILECTRICAL EFfECTS PRODUCED BY FRICTION. IQ/ 



" It will afford me much pleasure (says Dr. Maycock) Theory of 

 " should these observations call the attention of your readers to^Jte^gnf je^ 

 " the theory of electrical excitement. I trust that, while we are serves atten- 

 " successfully employing the powers of electricity in chemical '^°"' 

 " analysis, we shall not altogether neglect to investigate the 

 " means by which these powers are called forth, and the laws 

 " by which their action is regulated. It has, with much in- 

 " justice, been objected to //zeor^^ica/ pursuits, that they lead 

 " to none of the practical advantages, which interest the happi- 

 " ness of society. The remark is indeed true, if applied to 

 *' particular discoveries ; but these are to be considered only as 

 " the elements from which physical science first took its ori- 

 " gin, and by which it is daily nourished and supported. Let 

 '' it never be forgotten, that our most perfect instruments, 

 " those which promote no less our comfort, than they tend to 

 " advance our intellectual improvement, are the invaluable 

 " fruits of philosophy." Journ. vol. XXXI, p. SOp. 



1. In quoting this passage with approbation, I cannot. Sir, ^^'^^**°^ f"*^- 

 u * • u .TA ,^ , 1 tion before ex- 

 but express again my regret, that Dr. Maycock appears to have amined. 



no knowledge of my papers in your Journal j for they might 

 have given him the opportunity of useful examinations between 

 us. For instance, in your No. J 26, for January, ISU'^, is my 

 paper under the title of Experiments, showing the effects of 

 Friction between bodies ; which experiments might have af- 

 forded him what he wishes to find in your readers, viz. some 

 remarks to be compared with his theory. But if he reads my 

 present paper, there will be only a litde time lost, and the ex- 

 amination may now be effected more directly between us 

 in your Journal. 



2. Dr. Maycock's system on the effects of friction is de- ^'■.- ^»ycocIc'« 

 rived from his opinion, which, in my former papers, I have t^gj, gjj-gg^,^ 

 proved to be unfounded, viz. that the electrical effects produced 



by the association of two proper metals appeared only when 

 they came to be 5epara^erf. Had Dr. Maycock known these 

 papers, he certainly would have thought it proper to answer 

 me, before he took his system as a principle in explaining the 

 effects of friction, as he does thus in vol. XXXI, p. 305. " It 

 " must be obvious, that, while we are drawing one body over 



* Vol. XXVIII, p. 1. 



another. 



