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their Effed 5 and that the Effed which they are able 
to perform, muft be equal to that of Leathern or 
Wooden Bellows of the fame Capacity, in containing 
an equal Quantity of Air. 
As to the Advantages which this new Invention has 
in regard to thojfe ufed hitherto, it is a known Thing, 
that the Power which works your common Bellows 
ufed at Iron Furnaces, muft be fufficient not only to 
comprefs the Bellows, but at the fame time to force 
down the Leaver with its Weight or Counterpoife ; 
which Leaver ferves again to raife the Bellows , when 
the Cog or Button on the Axle-tree of the Water-- 
Wheel Aides off from the Bellows tree , fo that the 
Power muft be fufficient at once to produce two dif- 
ferent Effeds; whereas thefe new Water-Bellows 
require fcarce any greater Power but what isneceffary 
to overcome the Fridion near the Centre of Mgtion, 
or the Axis C ; for in this my Invention an Advantage 
is obtain d,_ which very rarely happens in Mechanics, 
viz. That the Weight to be moved is 7 as here , on the 
Balance in /Equilibrio 5 fince the Bellows A and A 
cannot be otherwife conceived than as two equal, 
though heavy Weights in a pair of Scales, which ba- 
lance one another, although their Weight be everfo 
great 5 fo that, if each of thefe Bellows ffiould weigh 
a Tonn, they muft ftill equiponderate 3 which is fo 
much eafier attain'd to, fince it requires very little Art 
to make them both of a Weight, and order them at 
equal Diftances from the Centre of Motion. It is 
confequently known how fmall a Power is requir'd 
to fet the. Scales of a Balance with equal Weights in 
Motion, notwithftanding the Weight may be as great 
a$: 
