MR. GREGORY ON MECHANIC POWER, j 



*«ithor, that they cannot fubfift in any of the habitable parts 

 of the globe. But from the eternal cold of the polar regions, 

 where water remains for ever a folid mafsi, and iron cannot 

 ruft, he thinks we may reafonably look to thefe regions as the 

 native place of fuch bodies. In this he infifts there is nothing 

 impoffible, or even improbable. And why (hould thofe whence they 



i j j c i • . i -A. .1 • • are convc y c * t» 



meteors, he demands, ot which we know neither the origin, p t j, er p: . rts ^ 



the combuftibles that afford them aliment, the impulfe by meteors. 

 which they are moved, nor the nature of the lines they 

 defcribe in their courfe, be lefs capable of tearing them from 

 fome part of the globe, than pf forming them, contrary to 

 all physical probability, from elements which the atmofphere 

 can neither create nor hold in folution ? 



III. 



Farther Re?narks on Mechanic Power f in Reply to Mr. J. C. 

 Hornblowtr. //» a Letter from Mr.O. Gregory, Royal 



Mil. Academy. 



To Mr. NICHOLSON. 

 SIR, 



J. AM forry to be under the neceflity of troubling you with Prefatory 

 a few observations for infertion in your Journal, in confequence rcmar *' 

 of being called upon by Mr. Hornblower, as though it were 

 to defend fome newfangled doctrine, when the pofitions in 

 my former letter, which that gentleman thinks proper to cen- 

 fure, are in perfect conformity with the principles aflumed or 

 demonftrated by every correct writer on mechanical philofophy 

 fince it has been placed upon its proper bafis in the Principi* 

 of Newton. The fubje<5t I am now invited to difcufs, has fo 

 frequently been exhibited in the cleareft light by various 

 authors, both in England and on the Continent, that I fhould 

 rvot think myfelf juftified in occupying many of your pages 

 by an elaborate diflertation ; put of regard, however, to fo 

 refpedtable a correfpondent as Mr. H. J cannot help entering 

 a little into the difcuffion, though I am, I confefs, quite unable 

 to afcertain whether his laft letter is meant tooppofe my former 

 remarks, and thofe of Profeflbr Robifon with ferious argu- 

 ments, or is merely intended as ajeu d'ejprit. 



It 



