Effect of Temperature on the Viscosity of Gases. 199 

 Pipe No. 1. — Watek (see fig. 2a, page 190). 



Pipe No. 2.— Gas. 





Air. 



V B = 2-413 (feet per second)^/ \\ + m > 



V w = 997 (feet per second )*/j!±± 



461 

 461' 



XXIX. On the Effect of Temperature on the Viscosity of Air and 

 Carbon Dioxide. By Silas W. Holman, Associate Professor 

 of Physics in the Massachusetts Institute of Technology* . 

 [Plates I. & II.] 



THE investigation described in the present paper is a con- 

 tinuation of the work done on the same subject by the 

 author in 1876f . The experimental portion of the work con- 

 sists of about 250 independent measurements of the viscosity 

 of air and 140 of carbon dioxide (carbonic acid), besides some- 

 what extended incidental researches on thermometry. The 

 temperature-ranges for air were from 0° to 124° C. ; for car- 

 bonic acid, from 0° to 225° 0. The plan adopted at the outset 

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

 of apparatus ; then to proceed to the study of several gases 

 which have been already well investigated, either in regard to 

 tJieir viscosity or other properties, making measurements of 

 the viscosity at temperature-intervals of about 20° from low 

 to high temperatures. But the laborious nature of the obser- 

 vations, and the large amount of time demanded by the 

 observations and their reduction, have rendered the fulfilment 



* Communicated by the Author, being a slight abridgment of a paper 

 read before the American Academy of Arts and Sciences, May 13, 1885. 



t " On the Effect of Temperature on the Viscosity of Air," Proc. Amer. 

 Acad. Arts and Sci. xii. (1876) p. 41 ; Phil. Mag. iii. p. 81 (1877) j Wied. 

 Beibl i. p. 222. 



P2 



