2OO Experiments on the Production of Air 



sible upon the silk in the water, taking care at the same 

 time that the water should not acquire a greater heat 

 than that of about 90 F. Things had not remained 

 in this situation above 10 minutes, when I plainly 

 discovered the air-bubbles beginning to make their 

 appearance upon the surface of the silk, and at the 

 end of 6 hours there was collected at the upper part 

 of the globe a quantity of air sufficient to make a 

 proof of its goodness with nitrous air ; and, upon 

 trial, I had the pleasure to find that it was dephlagisti- 

 cated y and of such a degree of purity that i measure 

 of it with 3 measures of nitrous air occupied no more 

 than 1.68 measure. 



I afterwards exposed to the same light, in small in- 

 verted glass jars, filled with water, a fresh-gathered 

 healthy leaf of the peach-tree, and a stem of the pea- 

 plant, with three leaves upon it ; and both these vege- 

 tables furnished air in the same manner as they are 

 known to furnish it when exposed, under similar circum- 

 stances, to the action of the sun's direct rays, but in less 

 quantities, which I attribute to the greater intensity of 

 the sun's light above that of my lamps. 



The experiment with the silk and water I repeated 

 several times, always with nearly the same result. The 

 quantity of air furnished was sometimes a little greater 

 and sometimes a little less, but it was always in much 

 greater abundance than that furnished by an equal quan- 

 tity of water and silk exposed to the same heat, but ex- 

 cluded from the light ; and I have reason to think it was 

 of a much superior quality, though the quantity of that 

 produced in the dark was too small to be submitted to 

 any proof. 

 These experiments appear to me to be of so much im- 



