LIQUIDS AND ALLIED EXPERIMENTS. 



67 



The diffusion coefficients of hydrogen, computed from table 23, are 



r = 0.080 c.c./day or io 10 k = 3.4 



They are again larger than found in Chapter II ; but the differences are such 

 as might be ascribed to differences of composition, seeing how extremely 

 sensitive the method is to slight impurities in the diffusing gas, which can 

 not be kept rigorously pure. There remains the inherent temperature 

 effect, the influence of which on diffusion proper (apart from solution) has 

 yet to be investigated, both for hydrogen and for air. It is noteworthy, 

 however, that the k of the present observations, i. c, in a diffusion column 



Table 23. — Hydrogen-hydrogen through water. Vessel H (double tube). M = 1 1.653 

 grams; p Q = 2.jfi6; £=41.85; float, 2r = 3-05 cm.; tube, 2^ = 3.4 cm.; vessel, 

 2r = 4.6 cm. 



Date. 



Barom- 

 eter. 



' 



// 



Uo 



Date. 



Barom- 

 eter. 



t 



II 



t'o 



.Sept. 17. . 



76.24 





 22.5 



,, M 



6.041 



Oct. 7.. 



75.68 





 20.0 



61 .92 



5.281 



18.. 



76.06 



21.5 



69.75 



5.922 



8. . 



76.34 



20.2 



61 . 10 



5 



208 



19. . 



75-85 



22.0 



69.7I 



5.910 



9. . 



76.78 



21.8 



60.30 



5 



"5 



20. . 



7 ( >-°3 



23.0 



7O.5I 



5-959 



10. . 



76-27 



23.0 



60.04 



5 



074 



21 . . 



76.90 



I9.6 



70.20 



5-995 



11 . . 



76.72 



22.0 



58.88 



4 



992 



23.. 



76.81 



l8.2 



70. l6 



6.017 



12 . . 



76.40 



22.9 



58.41 



4 



938 



24.. 



77.00 



l8.2 



70.30 



6.029 



14. . 



76.88 



22 . 7 



56.42 



4 



772 



25.. 



76.72 



18.2 



70.22 



6.023 



15. . 



76.08 



22.7 



55-23 



4 



672 



26. . 



76.54 



18.4 



7O.O7 



6.006 



16.. 



76 . 92 



20.0 



53-57 



4 



569 



27.. 



76.31 



18.4 



69.84 



5.986 



17.. 



76.44 



20.8 



52-59 



4 



475 



28.. 



j 77 04 



19.9 



69.73 



5.950 



18. . 



76.38 



22.4 



52.20 



4 



420 



30.. 



76.90 



I8.0 



68.86 



5.910 



19. . 



: 75-97 



22. 1 



51.23 



4 



342 



Oct. 1 . 



i 76.03 



I8.4 



67-34 



5-772 



21 . . 



77.29 



21.4 



48.79 



4 



144 



2. . 



J 76.58 



I9.O 



66.67 



5-7°4 



22. . 



77.08 



21.3 



47.42 



4 



029 



3-- 



! 76.33 



20.7 



66.01 



5.618 



23. . 



76.05 



22.4 



46.54 



3 



941 



4.. 



! 76 . I 



23.O 



65.78 



5.560 



24. . 



75-29 



23 -5 



45-71 



3 



857 



'•• 



76 . 69 



21 .O 



64.47 



5.482 













nearly constant in diameter, comes out larger than it was found above for 

 a widening column. In any case the true diffusion coefficient for rigorously 

 pure hydrogen is yet to be found, inasmuch as the small admixtures in 

 question have so marked an effect. Thus the gas in the gasometer which 

 is used for the artificial atmosphere, even if generated quite pure, soon 

 becomes appreciably less so, since it must suffer contamination with the air 

 diffusing through the water of the gasometer over which the hydrogen is 

 stored. Since such large quantities are needed, mercury storage is nearly 

 out of the question. Hence the work with hydrogen was abandoned tem- 

 porarily at this stage, the coefficient last found, io 10 fc=34 * or tne volume 

 diffusion at o°C. and normal pressure, being preferable. 



43. Diffusion of Air into Air Through KC1 Solution. — The solution of 

 KC1 contained, after mixing, about 120 grams in 600 c.c. of solution. Its 

 density was found to be 1.1133 at 24.5 . From this a table of densities 

 P„, was computed between 16 and 25 , assuming the expansion to be the 



