Salusbury, Thomas, Mathematical collections and translations (Tome I), 1667

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1But although the Column ſtand erect at Right-Angles, yet for all
that, the Riſe along the Screw, folded about the Column, is not of
a greater Elevation than of 1/3 of a Right Angle, it being generated
by the Elevation of the Chanel A C: Therefore if we incline the
Column but 1/3 of the

ſaid Right Angle, and
a little more, as we ſee
I K H M, there is a
Tranſition and Moti­
on along the Chanel
I L: Therefore the
Water from the point
I to the point L ſhall
move deſcending, and
the Screw being turned
of it ſhall ſucceſſively
diſpoſe or preſent
themſelves to the Wa­
ter in the ſame Poſition as the part I L: Whereupon the Water
ſhall go ſucceſſively deſcending, and in the end ſhall be found to
be aſcended from the point I to the point H.
ble a thing it is, I leave ſuch to judge who ſhall perfectly have un­
derſtood it.
And by what hath been ſaid, we come to know, That
the Screw for raiſing of Water ought to be inclined a little more
than the quantity of the Angle of the Triangle by which the ſaid
Screw is deſcribed.
Of the Force of the
HAMMER, MALLET, or BEETLE.
The Inveſtigation of the cauſe of the Force of theſe Percuti­
ents is neceſſary for many Reaſons: and firſt, becauſe that
there appeareth in it much more matter of admiration than
is obſerved in any other Mechanick Inſtrument whatſoever.
For
ſtriking with the Hammer upon a Nail, which is to be driven into
a very tough Poſt, or with the Beetle upon a Stake that is to pene­
trate into very ſtiffe ground, we ſee, that by the ſole vertue of the
blow of the Percutient both the one and the other is thruſt for­
wards: ſo that without that, only laying the Beetle upon the
Nail or Stake it will not move then, nay, more, although you
ſhould lay upon them a Weight very much heavier than the ſaid
Beetle.
An effect truly admirable, and ſo much the more worthy
of Contemplation, in that, as I conceive, none of thoſe who have