THE STRUCTUKE OF THE NUCLEUS. 



47 



TABLE 23.— VALUES OF iV^ = 10^ (i+«oiog^ 



y = (/»/^o) ''-' = .92 



b =■ .10 

 / = 3-5 



25. Correction for precipitated moisture. — The method of paragraph 17, for 

 computing the actual number of nuclei between isothermal and adiabatic numbers, 

 when extended to the double drum, gives /> = 76, />'= G8, S = 21»3°, and therefore 

 S'= 283.3° as a first approximation. Inserting these data witii r = 582 and 

 /■'= 580 in the equation for entropy, the approximate value, 1 — a? =r .0243 grams 

 of water precipitated per gram of mixture, results. This is equivalent to .204 

 calories evolved per gram of aii' by the precipitation of the available 

 17 X 10" ^/12 X 10~4 =:::.0143 grams of water. The I'ise of air temperature is 

 thus .86°. 



Hence the new data are S = 293°, S'= 283.3° +.9°, and these with the above 

 values of r and r' give 1 — a' =.021 grams of water. Thus, 17.2 X 10 « X 21 X 

 lO"-"* = 361 X 10" 8 grams are precipitated per cub. cm. of moist air. If, as before, 

 5 X lO"* nuclei are present at the outset, the volume of each precipitated cloud 

 })article is 7.2 X 10" i'- cub. cm., and its linear dimensions therefore about 

 1.9 X 10-4 cm. 



To compute // in the equation for taljle 19, where 



{i+bt)\ogy 



N= 10 



the equation 



P' 

 •^ ft 





may be assumed ; whence log y = —.0379 ; and since I -\- bt = 1.35 



iV=10 



.512 z 



In this way the values marked iV iu tai)le 19 were computed. 



DISCUSSION. 



26. Data for coronal and axial color compared. — If the data ior the drum, 

 table 23, and those for the globe, tables 4, 9-12, be compared for the same axial or 

 flame color, the latter will be seen to be about three orders in advance of the others. 

 This is equivalent to a greater initial nucleation in case of the globe where the 

 exhaustion was greatei-, so that in like apparatus more exhaustion would subse- 

 quently also be needed for the globe, if the same color is to be reached in both 



