18 MR..). II. :IMNI1.KY OX AX EXPERIMENTAL IXVKSTICAT1OX <>F 



SECTION XL On the Effect of Altering the Condition of the Steam below the 



Orifice. 



The preliminary experiments and those numbered 1 to 10 in Table III. were made 

 with steam from a Lancashire boiler. The steam was withdrawn upwards from this 

 Iwiler through a channel consisting of f-inch unlagged steam piping, which passed 

 2'5 feet vertically, then 64 feet horizontally, and finally 97 feet downwards to the steam 

 chest. This great length of piping ensured a great amount of wetness in the steam 

 when received in the steam chest. In the later experiments the steam was taken 

 from a locomotive boiler much nearer the apparatus, the length of the connecting 

 pipe (f-inch steam piping) being 39 feet. In Experiments 19 to 24 this connecting 

 pipe was well lagged with rough felting, as was also the steam chest ; but, comparing 

 the results of Experiments 19 to 21 with those of Experiments 8 and 9, which were 

 made under the same initial conditions, or the results of Experiments 22 to 24 with 

 those of Experiments 1, 2, and 3, it is shown very clearly that, though the condition 

 of the steam in the steam chest when received from the boiler is very different in 

 the two cases, no apparent difference is obtained in the condition of the wiredrawn 

 steam. 



The same point is also made clear by comparing the results of Experiments 15, 16, 

 and 17. Experiment 15 was made with the channel from the boiler to the steam 

 chest unlagged, the other two being made with the channel well lagged. 



In Experiment 18, an attempt was made to alter, if possible, the initial dry ness of 

 the steam by working the injector for about 20 minutes during the experiment. This 

 may have the effect of sending over more priming water by creating a stir in the boiler 

 and also of introducing a little air into the boiler. A difference of 0'2 F. was all 

 that was obtained, this being less than the error of experiment. The results of this 

 Experiment 18, in which the steam pipe from the boiler and the steam chest were 

 well lagged, show no apparent difference from those of Experiments 10 14, during 

 which both the pipe and the steam chest were unlagged. 



As a further experiment on the same point, the author tried to find in Experiment 

 20 the effect of altering the boiler pressure, the pressure in the steam chest being kept 

 constant as usual. In this experiment, p l = 23 '4 Ibs. by gauge, or 36 '7 Ibs. per sq. 

 inch absolute, and p 2 = 20 "7 Ibs. The boiler pressure during the first part of the 

 experiment was 60 Ibs. by gauge, and during the latter part 90 Ibs., thus increasing 

 the amount of wiredrawing between the boiler and the steam chest considerably. 

 The mean temperature of the wiredrawn steam was found to be the same both before 

 and after the alteration in the boiler pressure. 



This experiment was then continued to observe what effect an alteration in the 

 amount of drainage of steam over and above the water from the steam chest had upon 

 the temperature readings. Keeping p l and p 2 the same as above, it was found that 

 by almost closing the drain pipe valve so that only a very small quantity of steam 



