220 Prof. Silas W. Holman on the Effect of 



for A in my results is 0*003637, with the same terms in the 

 equation. When methods as different in detail as those of 

 Obermayer and myself are in so close agreement as these 

 appear to be when thus discussed, the chances of large 

 constant errors other than those inherent in the use of trans- 

 piration methods seem to be much reduced. 



On the line J H are three points showing the results 

 obtained by Eilhard Wiedemann. The line is drawn from 

 the equation 



^=9 7o (l + 0'003727f-0'00000320^) 3 



which I have deduced from these three points. The curva- 

 ture is much greater than for either of the other lines, the 

 value of B being more than twice as great as in the lines 

 A and B, and three times as great as in C. A reference 

 to my discussion of the results for air will show that Wiede- 

 mann's results there exhibit similar relative characteristics. 

 Up to 100° for C0 2 the results differ numerically by less 

 than 0*7 per cent, from those of Obermayer and myself, but 

 at 200° the difference is nearly 3 per cent. 



The results by Puluj, as shown by the line O F, obtained 

 by oscillating plates, are smaller than all others, a difference 

 which characterizes his results for air. The range of tempe- 

 rature used is too limited to render the results available in the 

 present consideration. 



Conclusion. — In the absence of any really satisfactory 

 means of assigning proper weights to the results of Ober- 

 mayer, Wiedemann, and myself, it seems best to allow the 

 results to stand in the form above given, without an attempt 

 to deduce a mean. 



Air. 



In Plate II. are shown the residual curves for all available 

 observations on air. The line IJ, representing Maxwell's 

 results, doubtless owes its steepness to some large constant 

 error, for which several explanations have been offered. The 

 lines for 0. E. Meyer's results from capillary transpiration are 



o o 



AB from Eqn. t;=0-000171 (1+0-0024 1), Range 20 to 99 ; 

 CD „ 77 = 000170 (1+0-0028 0, „ 21 to 100; 



EF „ 7] =0-000174 (1 +0-0030 1), „ 21 to 100 ; 



and from oscillating plates the line is G H from the mean of 

 the equations, 



^ = 0-000186 (1 + 0-0030 0, 

 and 7? = 0-000189 (1 + 0-0025 t), range 19° to 82°, 



