1822.] on Mr. Herapath's Theory. 2^1 



lence " of disproving equally well not only the thing he would 

 wish, but every thing else, whether connected with it or not. 



Alluding to the loss and development of heat in the changes 

 of state, C. objects to Mr. H.'s theory of heat by motion, 

 *' because heat may for a time become imperceptible, and again 

 be developed, without bemp- destroyed ? " If, therefore/' says C. 

 " heat and motion be identical, motion cannot be destroyed, 

 which the experience of every day tells us is untrue." Here C. 

 would plainly charge Mr. H.'s theory as being incompetent to 

 explain, nay, as being repugnant to the phaenomena of latent heat. 

 Now observe, Mr. H.'s ** Theory of the Changes of State and the 

 Concomitant Phaenomena," in which the subject C. alludes to is 

 copiously explained, was published in the Annals for October ; 

 C. in his *' Observations," dated nearly a fortnight afterwards, 

 tells us he had seen this very number of the Annals^ and of course 

 this very explanation, for the want of which he gravely tells the 

 world Mr. H.'s theory is defective. Perhaps C.'s creative talent 

 can give some acceptable form to this nondescript offspring of 

 his fertile invention ? If this cannot be done, C. will find in the 

 December number the mathematical laws of the defect he com- 

 plains of numerically confirmed by the experiments of Ure, 

 Thomson, Dalton, Southern, Watt, Black, &c. Probably the 

 experimental testimonies of these philosophers may induce a 

 conviction of the validity of Mr. H.'s views, which, it is to be 

 hoped, C. will have liberality enough to acknowledge. 



Speaking of the gravific medium which Mr. H. confesses to 

 have adopted from Newton, C. says: ''Show me this fluid; 

 prove its existence." In the name of common-sense, and of all 

 that is reasonable, who, besides C. could have made so unac- 

 countable a request? What reply could C. expect from Mr. H. 

 to such a demand but this very natural one ? " Show me your 

 one or two fluids of electricity, of galvanism, and of magne- 

 tism ; show me your favourite fluid of caloric ; show me these, 

 or either of them, and by the very same means I will show you 

 the fluid you desire. " Prove the existence" of attraction, and 

 by that identical method, or those identical phsenomena, I will 

 'prove the existence' of my gravific fluid. '' Besides," Mr. H. 

 might add, " 1 will do more ; 1 will ^ prove its existence,' as I 

 have in p. 41 1 to 415, Annals for June, by other phaenomena to 

 whose solution you cannot apply the vulgar notions of attrac- 

 tion." This would be the natural reply of Mr. H. or of any one, 

 to so unexampled a demand. But the oddity of this odd request 

 is, " Show me this fluid." Surely C. does not require Mr. H. to 

 make this fluid visible? He does not wish, does he, Mr. H. to 

 catch and bring to him a nameless being, a few particles of a 

 fluid, which Newton says is so extremely subtile as to be able to 

 pervade the pores of the densest bodies with the utmost facility? 

 If such be C.'s desire, I feel persuaded Mr. H. will readily under- 



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