40O On the Chemical Prepertiei aitrlluUd it Light. 



particular kind of manner, that the motion of a (ingle fpark of fire, direflcd Into a powder- 

 magazine, will not only give motion to the building itfelf, and its contents, but will alfo 

 ihake a county ! 



Should this letter be thought unworthy of attention, or unfit for the public eye , I could 

 wifli, however, that you would oblige me fo far, if convenient, as to tranfmit it to Dr. Pear- 

 fon. I have the higheft opinion of his chemical knowledge, as well as of the liberality of 

 his principles ; and though I have plainly pointed out fome parts of his writings which I 

 think erroneous, I ftill hold him no lefs in eftimation. My only motive in making the ob« 

 jeftions and remarks which I have, is, if poflible, to arrive at truth. 



I am, with grateful efteem for the valuable information which 1 have repeatedly received 

 from your labours in the fields of fcience, Sir, 



Your moll obedient fervant, 

 Nov. 1 6, 1798. 



A conjlant Reader of your valuable Publications. 



Though I have Rated a few fafts and obfervations, I by no means wifli re be thought a maintaincr of any 

 of the theories alluded to in the text or the notes. — None of them appear to me to be eftablillved upon indubi- 

 table fafts. 



I 



V. 



An inquiry concerning the Chemical Properties that have been attributed to Light, B^ 

 Benjamin, Count of Rumfordy F.R.S. M.R.I. A* 



N the fecond part of my feventh effay, (on the propagation of heat in fluids,) I have men- 

 tioned the reafons which had induced me to doubt of the exiftence of thofe chemical pro- 

 perties in light that have been attributed to it, and to conclude, that all thofe vifible changes 

 produced in bodies by expofure to the a£tion of the fun's rays, are effedted, not by any 

 chemical combination of the matter of light with fuch bodies, but merely by the heat which 

 is generated, or excited, by the light that is abforbed by them. 



As the decifion of this queftion is a matter of great importance to the advancement of 

 fcience, and particularly to chemiftry, and as the fubjeft is in many refpedts curious and 

 interefting, it has often employed my thoughts in my leifure hours; and I have fpent much. 

 time in endeavouring to contrive experiments, from the unequivocal refults of which the 

 truth might be made to appear. Though I have not been fo fuccefsful in thefe itivefliga- 

 tions as 1 could wifli, yet I cannot help flattering myfelf, that an account of the refults of 

 fome of my late experiments will be thought fulBciently interefting to merit the attention 

 of the Royal Society. 



Having found that gold, or filver, might be melted by the heat (invifible to the fight) 

 which exifts in the air, at the diftance of more than an inch above the point of the flame 

 of a wax-candle, (fee my feventh eflay, part II. page 350.-t-) I was curious to know what cf- 

 feft this heat would produce on the oxides of thofe metals. 



Experiment No. I. Having evaporated to drynefs a folution of fine gold in aqua regia, I 

 diflfolved the refiduum, in juft as much diftilled water as was necefl"ary in order that the fo- 



* Philof. Tranf. J 798, p. 449. t OrPhilofi Journal, II. 165. 



lution 



