12 The Uses of

(ii .)

13. TT is easy to make an Estimate of the-*• great Quantities of Air, that are con-veyed by these Bellows: For suppose theMidriffs rife and fall one Foot at eachStroke, which is enough, and that sixtyTimes in a Minute, that will amount toseventy-five Tuns in a Minute, and fourThousand five Hundred in an Hour; whichwill amount to one Hundred eight Thou-sand Tuns in twenty-four Hours. And theTrunk P being a Foot square, the Velocityof the Air, as it pastes out thence, will beat the rate of three Thousand Feet in aMinute ; which is at the rate of thirty-fourMiles in an Hour. This, supposing noAir escaped between the Edges of the ri-sing and falling Midriffs, and the Sides ofthe Boxes, for which, an Allowance is tobe made; for which, supposing eight Milesare deducted, a large Allowance { Thatwill be nearly the Velocity with which aRacc-Horfc goes, who runs four Miles innine Minutes, which is at the rate of26.6 Miles in an Hour. And more than

thrice