330 APPENDIX. 
fphere, which Force does, as we fee, make 
the compreffed Air rufli out of the Bellows 
with great Velocity. 
2. Which Velocity I eftimated in the fol- 
lowing manner, niiz. by meafuring the Sur- 
face of the upper Board of the Bellows, and 
alfo the Space they defeended in a Second 
of time j whence having got the Quantity 
of Air expelled in that time, viz. four hun- 
dred and ninety five cubic Inches, this divi- 
ded by the Area of the Orifice of the Nofe 
of the Bellows gave eight hundred and twenty 
five Inches, or 6 %. 73 Feet, the Length of 
the Cylinder of Air, which ruflied out of the 
Bellows into the Fire in that time. Which 
Air being compreffed with a Weight -^th 
Parc greater than the Weight of the Acmo- 
fphere, its Quantity was Part of 45)^ 
cubic Inches greater, viz. 16. ^ Inches, in 
all 5 1 1. 5 cubic Inches of Air; which being 
thus forcibly impelled into the Fire with a 
Velocity of 6 S. 73 Feet in a Second of time, 
the Adion and Reaction between the elaflic 
vibrating Matter of the Fewel, and that of 
the Air, being thereby fo greatly increafed, 
as to caufe a moft intenfe Heat, fufficienc to 
melt Metals. 
The 
V 
