360 



Messrs. J. D. Fry and A. M. Tyndall on 



a diameter do not fit the theoretical values, and are moreover 

 too high to give a pitot constant of l'OO. The same is 

 probably true of: the other velocities, though the curves for 

 v — 76 cms. per second give no information on this point 

 because the flow was evidently eddy. 



Curves IV. 



i sr 



fP * 



n 



3 



--- ^ 



















\ 















V 



V 





! 



i 



i£^=*« 



"** -* 









-XI 



1 Ja. 







V 



V 



\\ 



\\ 





C/I 





- _ __ 



^^X\ 



VSu 



Ov 





\ 1 











X 



-^ 



Cv 











N 





Z 1+ 6 6 'o >K-r^5' 



When working at the lowest velocities it was important to 

 eliminate any errors due to temperature effects which might 

 be comparable with the small pressures observed. Thus if 

 the connecting tubes leading from the pressure-gauge to the 

 pitot are not at the same temperature, a spurious pressure 

 will be present which will only be eliminated by commutation 

 if such takes place close to the pitot ; at first it was 

 assumed that uniform temperature was obtained when the 

 connecting tubes were twisted together, but in all the later 

 work the commutator was placed as near the pitot as possible 



