192 



Lord Kelvin 



on 



of Vienna in 1870, Loschmidt describes experimental deter- 

 minations of the inter-diffusivities of ten pairs of gases made, 

 by a well-devised method, with great care to secure accuracy. 

 In each case the inter-diffusivity determined by the experi- 

 ment would be, at all events, somewhat approximately the 

 mean of the two diffusivities, § 39 above, if these are unequal. 

 The results reduced to 0° C. and standard atmospheric pres- 

 sure, and multiplied by 2*78 to reduce from Loschmidt' s 

 square metres per hour to the now usual square centimetres 

 per second, are as follows : — 



Table of Inter- 



DIFFUSIVITIES D. 



Pairs of Gases. 



in sq. cms. per sec. 



H 2 , 2 



•7214 



H 2 , CO 



•6422 



H 2 , C0 2 



•5558 



2 , CO 



1802 



o 2 , co 2 



•1409 



CO, C0 o 



•1406 



CO.,, Air 



•1423 



C0 2 , NO 



•0984 



C0 2 , 0H 4 



•1587 



SO,, H, 



• 



•4809 



In the first six of these, each of the four gases H 2 , 2 , CO, 

 00 2 occurs three times and we have four sets of three inter- 

 diffusivities giving in all three determinations of the 

 diffusivity of each gas as follows : — 



f Pairs of gases. D v 



' (12,13, 23) 1-31 



(12, 14,24) 1-44 



(13, 14, 34) 1-22 



Gases. 



H 2 

 CO 



co, 



Mean 1-32 



•(1) 



(3) 

 (4) 



D a . 



(12, 13,23) '168 



(13, 14, 34) -175 



(23,24,34) -172 



Mean '172 



Pairs of gases. 



B.,. 



(12. 13, 23) 



(12,14,24) 



(^3,24,34) 



•193 

 •190 

 .•182 



Mean 



•188 



(12,14,24) 



(13,14,34) 



(23,24,34) 



A- 



•107 

 •112 

 •110 



Mean 



•110 



