1906.] 



IN MEASURING PRESSURES IN A FLUID STREAM. 



81 



These disk collectors may also be used with perfect results in 

 water pipes, if the velocity is not great enough to produce discon- 

 tinuities where air would show rarefactions. No tests have yet been 

 made under these conditions. For high velocities the action of the 

 Pitot tube deserves a complete re-investigation. It seems probable 

 that the tube inclined at an angle of 60° with a Pitot tube will be 

 the best method of eliminating velocity effects in a current of water 

 at very high velocity. 



In measuring wind pressures on buildings by means of inclined 

 water gauges, the open end of the tube must be connected with a 

 large reservoir, which is connected to a horizontal disk collector, 

 far above the building. The disk is to be horizontal, so that the 

 air current strikes it edgewise. These disks are now being mounted 

 on the ^physics building of Washington University. Nearly a mile 

 of piping is being used in connecting the various collectors, each 





Fig. 2. 



with its own gauge. The details of the collector are shown in Fig. 

 2, in cross section. 



The two collectors here shown are presented to the society. 



PROC. AMER. PHIL. SOC, XLV. 182F, PRINTED JUNE 25, I906. 



