LIQUIDS AND AIvUED EXPERIMENTS. 



63 



a length of but 4.5 to 5.5 cm. and the experiment continued under these 

 conditions. The records are given in tables 18, 19, 20, and figs. 19 a, b, c, 

 the long swimmers showing astonishingly slow diffusion. Both were moved 

 to the vault of constant temperature on October 25. (Cf. c in fig. 19B). 



Table 18. — Air-air through water. Vessel E (single tube). M= 14.8968 grams; C= 53.5 1 ; 

 Pfl=2.466; float, 2r = 3.oo cm.; vessel, 2^=4.7 cm. 



Date. 



Sept. 30 

 Oct. I 



2 



3 



4 

 5 



7 



8 

 9 



Date. 



Oct. 



10 

 1 1 

 12 

 "4 

 '5 

 16 



«7 

 18 



«9 



Barom- 

 eter. 



H 



t'o 



76.27 

 76.72 

 76.40 

 76.88 

 76.08 

 76.92 



76.44 

 76.38 



75.97 



22.8 



21.7 



22.7 



22.5 



22.4 



19. 



20. 



22. 



22. 



68.51 

 68.31 

 68.61 

 68.50 

 68.33 

 67.23 

 67.03 

 67.49 

 67.49 



408 

 410 

 420 



413 



397 

 338 

 299 

 310 

 312 



Table 19. — Air-air through water. Vessel F (single tube). il/=23.5450grams; (7=84.58; 

 P(7 = 2.466; float, 2^ = 3.00 cm.; vessel, 2r = 4.7 cm. 



The identity of the two curves, figs. 19 a and B,in their indirect fluctuation 

 with temperature is noteworthy, showing that the relative results obtained 

 with a given apparatus are quite trustworthy. The new feature which the 

 curves bring out, however, is unexpected. In other words, the rate of 

 diffusion, which was incidentally found to be relatively large in table 16, 

 is here relatively small, only about one-tenth of the former value. If the 

 mean slope of the cur^'^e, fig. 19 a, be taken, the data for the diffusion con- 

 stants are 



^0 = 0.0042 c.c./day or io^*'k = 0.374 



where the curve of fig. 19 b for the same interval of time would have given 

 an identical result. It was therefore to be feared, in so far as these results 



