/- 



PROCEEDINGS 



OF THE 



AMERICAN ACADEMY 



OF 



ARTS AND SCIENCES. 



VOL. XXI. 

 PAPERS READ BEFORE THE ACADEMY. 



Investigations on Light and Heat, made and published wholly or in part with 

 Appuopmation from the Rumford Fund. 



CONTRIBUTIONS FROM THE PHYSICAL LABORATORY OF THE 

 MASSACHUSETTS INSTITUTE OF TECHNOLOGY. 



XX. 



ON THE EFFECT OF TEMPERATURE ON THE 

 VISCOSITY OF AIR. 



By Silas W. Holmax. 



Communicated May 13, 1885. 



Page 



Apparatus, Description of 2 



Procedure in Measurements 6 



Experimental Results 7 



Discussion of Results of all Researches on 

 Air and CO, 19 



Page 

 Critique of tlie Method, including Compar- 

 isons of Mercurial and Air Thermome- 

 ters 25 



References 44 



The investigation described in the present paper is a continuation of 

 the work done on the same subject by the author in 187G.* The ex- 

 perimental portion of the work consists of about 250 independent meas- 

 urements of the viscosity of air and 140 of carbon dioxide (carbonic 

 acid), besides somewhat extended incidental researches on thermome- 

 try. The temperature ranges for air were from 0° to 124° C. ; for 

 carbonic acid, from 0^ to 225° C. The plan adopted at the outset 

 was to make some study of the method and of the best form of appar- 

 atus ; then to proceed to the study of several gases which have been 



* On the Effect of Temperature on the ViseositVof Air, Proc. Amer. Acad. 

 Arts and Sd., xii. (187G), p. 4L Phil. Mag., iiF 81 (187(3). Wied. Beibl., 

 i. 222. 



VOL. XXI. (n. s. xm.) 1 ,., ■ 



