T. Guerin on the delivery of water from conduit pipes. 193 
02518172 7” +-0006769 x = (g24° 141724 gD2), 
If H be sides by this quantity and also by the friction 
due to the passing of Q through the length 7, the remainder 
must be equal to the head which forces the quantity Q through 
the length, NB, viz 
H—-0251817 z oa 00067695, (2+ 1417249D2) 
as ‘000676955 (Q?-4- 141724QD2), 
Let this quantity be cabetituted for H in the general value 
for Q as given above, and there will result 
Pee 1477°30D°5 
Q=- - £ —(q? 17249D3 
L+37- 20D t. WEE 505 (u bermagesl 0006769 (9 +°1417249 ") 
2D2 
é ‘00087694 (q2-4- £(a*+-14172400")) + ( sie (oroseaoeny 
~ Resolving nF) quadratic equation, the value of Q is found 
to be as follow 
—070862D*], cE areas 
_es T3730p 2* 0251817g2D)— 
“070862D7], 2 
+ (ear ‘iaD) 
Such is the value for Q in general; but when the velocity ex- 
ceeds two feet per second, and that of L is great compared to 37 
times D, in that case it will be seen by D’Aubuisson, No. 189, 
that @=37: 548 |HD*, and hence H =-0007089 44 1a" - Frenithis 
u st ‘ 
ETD) opi t 14172492) 
general value for H, it appears that 0007089 =; u 5 - is the head re- 
quired to force the quantity q to the point N; ee as it appears 
from D’Aubuisson, No. 187, that 0007089 ae is the friction 
due to the pom of Q through the length I; it follows that 
H—: ‘0007089 — 0007089 55; denotes the head which would 
be competent fn force Q trol the length NB. Let this 
quantity be substituted for H in the value for Q, and there will 
result Q=37°548 | |HD*>— oe lq? This is a convenient 
formula for Ate and it ees a correct result wher the veloc- 
ity exceeds two feet t per second, and when the senaeh is great 
AM. Jour. Sc.—SrcoxD Serres, Vou. XLV, No. 134.—Marou, 1868. 
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