Parry. — Resistance to Flow of Fluids throttgh Pipes. 



485 



1-7 to nearly 2-0. An examination of experimental results confirm this 

 view. Each experimenter has a different index, which varies, as a matter 

 of fact, between the limits mentioned. 



The diagram of fig. 2 affords a clear indication of the direction in which 

 further experiments upon riveted pipe should take, and it is evident that 

 no addition to our present knowledge can be made ; neither can a law be 

 for certain deduced unless the observations are extended so as to cover a 

 greater range. 



Regarding the results plotted in fig. 2, and taking curve a as a guide, it 

 is reasonable to assume that the curve will be of the same form as curve a 

 as expressed in equation (2) ; and, further, one might also reasonably assume 

 that the viscosity element is constant, and that the inertia effect is greater 

 because of the disturbing effect of the rivets and joints. Proceeding on 

 this principle, three curves — viz., c, d, and e — are drawn through the points 

 in fig. 2, c and e being drawn through what may be deemed to be the lower 

 and upper limit after neglecting what are obviously random or stray shots. 



Fig. 3. 



or errors in observation. Curve d is drawn through the thickest part of 

 the cluster, and may be deemed to represent the commonest or most usual 

 value. 



It will be seen that these curves are as likely to represent the true form 

 as any other, and there is ground to believe them to be the true repre- 

 sentation of the law. 



These curves have been transferred to fig. 1, curve a being the standard, 

 whilst c, d, and e are the same as c, d, and e in fig. 2. These may be expressed 

 respectively as follows : — 



Curve c 



„ d 

 e 



^lA— a)°'' 



+ -000052 



+ 

 + 



•000068 

 •000098 



Large numbers of experiments have been carried out on wood stave 

 pipes, and on this account it is instructive to plot observations in the same 

 manner as for riveted steel pipes. This is done in fig. 3, where a is the curve 

 for smooth pipes, as in figs. 1 and 2. 



