Convection from Wires in a Stream of Air. 907 



■of the curve. It may be mentioned that a curve between 

 H/& and vl/v plotted from this table is practically identical 

 with that, of fig. J, where allowance was made for the change 

 of the physical constants with temperature. 







Table II. 







Relation 



between Tv/p a 



nd B/k. 





i> = 6-145 



* 



log 



v=Fl6. 





& = 5'77 x 



10 



-*. log 



/c=:5'76. 



vl 



i H 



l0<* — 



° k • 





loo; — . 

 ° P 





1-015 



0-81 





1-88 



King (0 003 cm.) 



1-316 



0-93 





2-03 





1015 



0-84 





1-88 



(0-015 cm.), 



1-714 



112 





2-51 





2015 



126 





3-01 





3-14 



1-78 





5-09 



Hughes. 



3-84 



2-13 





6-54 





4-14 



2-30 





717 





4-44 



2-48 





7-79 





4-68 



2-64 





8-29 





2-05 



1-25 





3-08 



Kennelly. 



2-26 



1-31 





3-50 





2-40 



1-41 





3-76 





210 



1-26 





3-18 





2-40 



1-42 





3-76 





As stated earlier, the theory of Osborne Reynolds gives 

 for fluid flow through a given pipe 



H oc R/v. 



This simple relation does not hold for wires in the region 

 considered, for taking the straight line part of the curve of 

 rig. 3 it is seen that 



Hoc R°- 275 approx., (8)f 



* The value taken for v in the ' Report of the Advisory Committee for 

 Aeronautics ' differs slightly but inappreciably from this, and so no 

 allowance has been made for the difference. 



t With respect to the reality or otherwise of the unexplained dip in 

 the "Dynamical Relation" of fig. 1, little effect is made in fig. 3 by 

 smoothing out the dip entirely. Smoothing appears, however, to make 

 more uniform the tendency of the relation to take the Reynolds form as 

 vl/v increases. 



