290 M. F. Zollner on the Temperature and 



Now, if w be the weight of the air, the work of the elevation 

 of temperature 1° at constant pressure is 772wc, and at constant 

 volume 772 wc 1 ; therefore 



•° 02036 ^ V 

 772wc = 772wci-f 



and the weight of a cubic foot of air at 60° and a pressure of 

 14*706 lbs, per square inch being 535*68 grs., 



1 + -002036(^-32) ' 



of air at 60° and a \ 

 tg 535 '68 grs., 



_ 535-68;?V 1 + '002036(60 -32) , 



W ~ 7000x14-706x144 1 + -002036 (*- 32) ' 

 therefore 



_ '002036 x 7000 x 14-706 x 144 

 c - c *+ 535-68x772x1-057 



= (?, + -06906 

 Or, ifc = -2377, <?, = -1686. 



This difference, *06906, between the specific heat of air at con- 

 stant pressure and that at constant volume requires only to be 

 divided by the specific gravity (air being 1) of any gas or vapour 

 to obtain the corresponding difference for that gas or vapour. 

 The specific heat of aqueous vapour at constant volume thus 

 determined is -837 — '1110, or -726. 



XXXV. On the Temperature and Physical Constitution of the 

 Sun. (Second Memoir.) By F. Zollner*. 



§i. 



IN a previous memoir on the same theme f, I endeavoured to 

 ascertain boundary values for the minimum of the tempera, 

 ture at the surface of the sun and at a certain depth beneath it. 

 The method of this determination of temperature had for its 

 theoretical hypotheses the following : — 



1. The law of Mariotteand Gay-Lussac; 



2. The constancy of the ratio of the specific heats with con- 



stant volume and constant pressure ; 



3. The assumption that the eruptive protuberances are a 



phenomenon of the out-streaming of a gas. 



* Translated from a separate impression, communicated hy the Author, 

 from the Berichte der Km. Sachs. Gesellschaft der Wissenschaften, math.- 

 phys. Classe, February 21, 1873. 



t Ber. d. K. Sachs. Gesellsch. d. Wiss. June 2, 18/0. Phil. Mag. S. 4. 

 vol. xl. p. 313. Supplementary remarks will be found at the close of the 

 present memoir and in Natur der Cometen, p. 490. 



