.S7A 1 \\~II.1.IAM Sir.MENS, F.R.S. 



'45 



which gives a result of nearly four times the useful effect that was 



ii'-il in Zenner's apparatus. 



The following Table I. gives the results obtained with the steam 

 jet arranged as an exhauster for drawing air out of a closed vessel 

 having a capacity of 225 cubic feet. The four last columns show 

 the vacuum produced in the vessel, measured in inches of mercury, 

 when the exhauster had continued in action for the length of time 

 indicated in the first column. The pressure of steam in the boiler 

 was 45 Ibs.. per square inch, and the sectional area of the annular 

 steam orifice of thu jet was varied from 0'05 to 0'20 square inch. 



TABLE I. 



EXPERIMENTS WITH STEAM-JET EXHAUSTER EXHAUSTING AIR FROM 

 A CLOSED VESSEL. 



Time of 

 action. 



ARI:A OF AJTNIILA.B ORIKICK OK SIKVM .11:1 



o-n. - i sc|. in. 



0-10 8(i. in. 



0-10 s<|. in. 



o-J.i si|. in. 



Another set of experiments has been tried with the steam jet 

 used as a blower for compressing air into the same closed vessel 

 of 225 cubic feet capacity. For this purpose the conical delivery 

 funnel of the steam jet was connected with the vessel by means 

 of a 3-inch pipe containing a stop-cock ; and into this pipe was 

 delivered a small jet of cold water through a pipe of | inch 

 diameter under a pressure of 40 Ibs. per square inch, with the 

 object of condensing the steam from the blower, the water being 

 turned on simultaneously with the starting of the steam jet. The 

 sectional area of the outer annular air passage in the blower was 

 0'20 square inch, and of the inner air passage in the centre of the jet 

 T 1 1; square inch, making a total of 0'36 square inch of air section. 

 The sectional area of the annular steam jet was 0'07 and (fl 2 square 

 VOL. i. L 



