from Water exposed to Light. 201 



portance, that I could wish they might be repeated and 

 varied in such a manner as thoroughly to establish the 

 facts relative to the subject in question. For my part I 

 would most readily undertake the investigation of the 

 matter; but, being employed in another pursuit (the 

 continuation of my Experiments upon Heat), and, be- 

 sides this, much of my time being taken up by the duties 

 of my military employment, I have not leisure at pres- 

 ent for such an undertaking. 



Perhaps it may be proved by future experiment that 

 the matter of light is a constituent part of what is called 

 pure or dephlogisticated air; if so, may we not venture 

 to conclude with M. Scheele, that the light, as well as 

 the heat, produced by flame, and in general all burn- 

 ing bodies, arises solely from the decomposition of this 

 air, and not from the phlogiston or inflammable princi- 

 ple of the body which is burnt ? There are many phae- 

 nome-na which would seem to justify this opinion. 



But to proceed in the account of my experiments. 

 The operation of inverting the globes under water, and 

 placing them in the jars, and of displacing and replacing 

 them upon removing the air produced, being attended 

 with some inconveniences, I had recourse to another 

 method of disposing of the apparatus, much more sim- 

 ple and more convenient. The globes, being filled, were 

 laid upon a small piece of deal board, with their necks 

 inclined at an angle of about 20 above the plane of the 

 horizon, and supported in this position by a perpendicu- 

 lar fork of wood fixed to the end of the board, as rep- 

 resented by the following figure. The part of the board 

 upon which the under part of the globe reposed was 

 hollowed a little, to prevent the globe from rolling ; or, 

 what I found more safe and convenient, a small ring 



