248 A. deF. Palmer^ Jr. — Condensation in the Stemn Jet. 



where U is the velocity, v the mean specific volume at the 

 surface, m the mass of steam issuing from the nozzle in unit 

 time, and S the area of the surface ; m and v are obviously com- 

 plementary functions of the actuating pressure P of the jet, 

 and the effect of their product on the variations of U with 

 respect to P may be neglected in making the approximate 

 determinations which alone are possible at the present time. 

 For the calculation of S and its dependence on P a series of 

 photographs of the jet were made and estimations attempted 

 from measurements of the negatives, but it was found impos- 

 sible to produce images having sufficient detail throughout to 

 permit of accuracy by this method. However, the distance D 

 from the plane of the nozzle to the lower limit of the surface 

 could always be quite accurately determined, and, as this quan- 

 tity varies directly with S and hence inversely with U, its 

 values for different values of P serve as an index to the changes 

 in U. Hence, while it is impossible to determine the absolute 

 condensation velocity under any given conditions, a general 

 idea of the nature of its variations may be obtained from a 

 series of measurements of the distance I). 



1. 



J 



t^ 



D 



B 



A brass compressed air tank of about three gallons capacity, 

 heated by a large Fletcher burner and fitted with a Bourdon 

 gauge reading from zero to thirty pounds pressure, was utilized 

 as a boiler and connected by quarter-inch gas pipe to the dry- 

 ing apparatus illustrated in tig. 1. Here C is a chamber about 

 three inches in diameter by eight inches high, made of steam 

 pipe and connected at A with an open tube mercury manom- 



