THE 



AMERICAN JOURNAL OF SCIENCE 



[FOURTH SERIES.! 



Akt. XXXIII. — On the Rate of Condensation in the Steam 

 Jet; bj A. de Forest Palmer, Jr., Ph.D. "With Plate lY. 



During his investigation on " The Condensation of Atmo- 

 spheric Moisture," Prof. Barus,^ while working with a steam 

 jet, observed that the region of condensed vapor terminated 

 below in a surface similar to that surrounding the inner part of 

 a Bunsen flame. Its lower limit was parallel to the plane of 

 the nozzle and at a distance above it depending on the actu- 

 ating pressure of the jet. At this surface the velocity of con- 

 densation downward is equal to the upward velocity of the 

 steam, and this in turn is an inverse function of the distance 

 from the origin. From a few preliminary measurements he 

 was led to the opinion that the condensation velocity increased 

 very rapidly with the pressure, and at his suggestion I have 

 undertaken a further investigation of the subject by a photo- 

 graphic method similar to that employed by W. Michelsonf in 

 his study of the combustion velocity of explosive gas mixtures. 



The calculation of the absolute velocity of condensation at 

 any instant involves a knowledge of the specific volume of the 

 steam and the curvature at every point of the surface of sepa- 

 ration between the regions of condensed and non-condensed 

 vapor. It is, however, probable that these two quantities are 

 so related that the normal velocity is constant over the entire 

 surface and hence may be expressed by the simple formula 



_ vm 

 "S" 



* Bulletin No. 12, U. S. Department of Agriculture, Weather Bureau, 1895, p. 

 87. 

 f Wied. Ann., vol. xxxvi, p. 1, 1889, 



Am. Jour. Sci.— Foitrth Series, Yol. II, No. 10. — October, 1896. 

 18 



