214 Of Winds and Sounds.

if we reflect on the Nature of the Particleof a sonorous Body and those of Air>

shall

a given Time. Let us now suppose B = B ; then j??,cause D : D :: 860 ; i, (See Annot. LXXXlX- *'•we have E : E :: 860 V* = : F 2 ; and lastly, if we s u P'pose the Effects to be equal, viz. E — E, then we h aV

860 V 2 = F 2 . Therefore if we put Y = r, we have

8 6?

— F 2 ; and so F= \/86o — 2 9>3 z6 J that is, ^locity of Air ought to be somewhat more than 29greater than that of Water to strike a given Surfacethe fame Force. , .

13. Indeed Mr. Belidor makes V — 25s, b eC . aU t0he has strangely mistaken the specific Gravity of Ah

be -i-, instead of -i-, on which Account all b 15640 86o ? - - [CS

Calculations on this Head are very faulty. If V den® ^any equable Velocity of Water, the Height H of 3 *^necessary to produce that Velocity is thus found,

32 : \/\6 (=4) :: V : \/H ; or thus, As 1024 : ^

16 V 1 V 2 - ■ .

V 2 : H = orputtingV=:x,wehaveD^

1024 64 r 0

£ . Now a cubic Foot of Water, whose Height is

strikes with a Force — 62,5 Ib. ; therefore the Fo r ^ f<a Column, whose Height is H, striking against 3 y*

62 e 620^

face of one Square Foot is 62,5 H — or = "^4when the Velocity is not given,

V 1 ,

-, therefore "As

of-

14. But (by Art. |2.) V 1 =

000

62,5

X - v ~ ~ — 62,5H — 0,976 Ib. the Force or a.94

Column of Water whose Velocity is V — r, an “ , 0 f awhose Velocity is F — 29,3, and Height H ^

F 2 ' he 3

Foot; therefore—X 0,976 — 0,00113 F 2 W1 ‘

000 AblO'f*

constant Multiplier to reduce the Force of Wind jpg