102 PROFESSOR A. H. GIBSON ON THE RESISTANCE TO FLOW OF WATER 
§ 3. Errecr oF PROJECTING SMALLER PipE INTO SPacE BOUNDED 
BY DIVERGENT WALLS. 
For the purpose of examining this effect, a thin sleeve of internal diameter ‘90 
inch and external diameter 10 inch was prepared and used inside the various 1-inch 
pipes, as shown in fig. 2. 
The length / of the internal projection was varied by varying the thickness of the 
washer W. ‘The pressure in the smaller pipe was measured at two points distant 
respectively 12 inches and 20 inches from the open end, and the pressure at this end 
was deduced from these readings on the assumption that the friction loss per unit 
Fie. 2. 
length of the pipe is constant. The percentage losses in a conical pipe with initial 
and final diameters ‘90 inch and 3°0 inches respectively are very sensibly the same as 
in one with initial and final diameters 1°0 inch and 3:0 inches, and the losses actually 
observed with the projecting pipes are therefore given, for comparison with those 
given by the latter pipes. 
The results of the experiments are as follows :— 
Percentage Loss of Head. 
Value of 6 . : : 40° 60° 90° 
Pipe with diameters 
1 in. and 3 in, : 80:87 101°37 104.1% 
Ae aes : | Pipe projecting— Pipe projecting— Pipe projecting— 
eee ee with | 50 in.. . 98:0%| -25in.. . 1045%|-25in, . . 107-7% 
sages “1 100 in. 7 MORO) 50 ame se OTe, 
and 3 in. : 67 
PrO0in. |. Lio 7 
