Nipher — On Pressure Measurements in a Fluid Stream. 29 



zero setting were in very close agreement, and they have been 

 combined in the averages. 



The |/mean square velocity of the train while these read- 

 ings were taken was 41.8 miles per hour. The corresponding 

 relative velocity of the train, with respect to the air at the 

 point occupied by the collecting tube was 32.5 miles per hour. 

 This lesser relative velocity was due to the fact that air is 

 dragged along with the train. 



Pressures in Pitot Tube Whose Axis Mabges an Angle 

 a WITH AN Air Current of Constant Velocity. 



