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520 PHILOSOPHICAL TRANSACTIONS. [aNNO 1741. 



before, there remains only 14 oz. the difference, which shows that all the air 

 was nearly excluded out of the globe by the steani : in ounces it stands thus 

 which is very nearly a perfect vacuum. 



2dly, He again excluded the air out of the globe with steam as before, and 

 both cocks B, B, being closed with the globe full of steam, he put the globe in 

 the scales, and it weighed 12 lb. 104- oz. He then opened one of the cocks, 

 and let in the air, on which the scale descended; and, by adding weight in the 

 other scale, it was found to weigh 12lb. 11 oz. ; which showed that the weight, 

 not the pressure, of the air the globe contained, was 4- an ounce avoirdupois. 



3dly, the globe being filled with steam, as before, and condensed with cold 

 water on the outside of the globe, and the metal again made very dry, and the 

 air let into the globe, the water from the condensed steam was found to weigh 

 4 penny-weights. 



4thly, The globe filled with steam, as before ; only now he continued the 

 globe longer with the steam passing through it, by which it acquired a greater 

 degree of heat ; for he found by those experiments, that the least degree of 

 cold less than the steam, a part would be condensed again into water, by which 

 the quantity could not be certainly ascertained, which would exclude the air out 

 of a certain space, which is the chief end of this experiment. But in this ex- 

 periment he succeeded better ; for, on weighing the globe, when the steam was 

 condensed, the air let in, and all cold, it was as follows, viz. 15 lb. 3 oz. 2 dwts. 

 Troy, the weight without the steam being 15 lb. 3 oz. ; so that the weight of 

 the water condensed from the steam, or the water converted into a strong elastic 

 steam to fill the space of this little globe, is but 2 dwts, or -^V of an ounce Troy 

 of water, by which -rV of an ounce Troy of water fills, when converted into 

 steam, 925 cubic inches of space in a vessel, so as to exclude nearly all the 

 air. 



He repeated this experiment several times, and found it nearly the same; and 

 by immersing the cock in water, and opening it again, as in the first experi- 

 ment, he found the weight of water to be nearly as above, and to make about 

 -!^ void or vacuum ; so that 1 ounce Troy of water makes 9250 cube inches of 

 steam, of equal force with the like number of inches of air ; and with this re- 

 mark, that the weight of the steam is much less than the weight of common 

 air ; for in this globe the air weighed -i- oz. avoirdupois or g dwts, Troy ; and 

 the steam, which filled the same space, only 2 dwts. Troy, which is but little 

 more than -i-th part, and shows how very small the particles of water are when 

 so divided by the force of fire, and of what force. From which he concludes, 

 that 1 cubic inch of water will discharge or force out 40O0 inches of air from a 

 vessel of that content. 



5thly, Proceeding as before with steam in the globe a ; he condensed it, as 



