336 Mr. A. H. Davis on Natural 



Table IV. 



Convection Loss from Wire in Various Gases, 

 at various pressures. 



Wire diam. O1106 cm. 



Source. 



Gras. 



|Pressure 

 Atm. 





Temperature 



Excess 



(° C). 



100°. 



300°. 



900°. 



9d 3 



H 



9d s 

 v 2 ' 



H 



1' 



9d 3 



H 



7c' 



E 



Air 



o-i 



2-48 



0-40 



2-59 



0-45 



2-34 



0-53 







10 



0-48 



063 



0-59 



0-64 



034 



0-67 







10 



2-48 



0-95 



2-59 



097 



2-34 



0-99 







100 



4-48 



1-47 



4-59 



1-44 



4-34 



1-39 



F 



Hydrogen . 



01 



482 



034 



491 



0-34 



4-69 



0-38 





1-0 



2-82 



0-38 



2-91 



040 



2-69 



044 







10 



0-82 



0-60 



0-91 



0-68 



0-69 



062 







100 



2-82 



1-00 



2-91 



103 



2-69 



0-99 



G- 



Oxygen ... 



o-i 



10 



2-47 

 0-47 



0-40 

 0-66 



2-56 



0-56 



0-44 

 066. 



2-30 

 030 



0-57 

 0-67 









10 



2-47 



0-93 



256 



095 



2-30 



096 







100 



447 



1-47 



4-56 



1-45 



4-30 



1-45 



In fig. 1 all the Langmuir values of Table III. are 

 plotted. 



(B) Ayrton and Kilgour * worked with fine wires at more 

 moderate temperature excesses. Table III. contains values 

 for all their wires, but for convenience fig. T only shows 

 values for the largest and the smallest. It s,hould be 

 mentioned that one wire (0*0074 cm. diam.) gives results at 

 low temperature excess in poor agreement with the line in 

 fig. 1. However, study of their curves shows that the 

 behaviour of this particular wire is exceptional. 



(C) Petavel f has given data for the total heat loss from 

 the oxidized iron surface of steam pipes of various diameters 

 up to 1 foot, a diameter which is ten thousand times the 



* Ayrton & Kilgour, Phil. Trans. A, clxxxiii. p. 371 (1892). 

 t Petavel, Proc. Manchester Assoc. Engineers, 1915-16. 



_ 



