r, 



MR. .T. II. GRINDLEY ON AN EXPKKIMKNTAI. INVESTIGATION OF 



diameter, thus pi-eventing any material transfer of heat through the fastenings from 

 the saturated steam to the wiredrawn steam. 



The use of glass, however, increased the experimental difficulties considerably, for 

 it often happened that the orifice plate would break during the heating of the 

 apparatus, necessitating its removal and the insertion of a fresh plate before the 

 experiment could be proceeded with. In the later experiments, made with great 

 differences of pressure, the area exposed to this difference of pressxire had to be 

 reduced considerably for the plate to bear the combined differences of pressure and 

 temperature. A full-size sectional view of the orifice plate and fastenings is shown 

 in fig. 1. 



Fig. 1. 



GG, glass plate. 

 RR, copper rings. 



SECTION V. Description of Apparatus. 



A front view of the main portion of the apparatus is shown in fig. 2, RR being a 

 vertical cylinder, forming a reservoir in which the steam is received through the pipe 

 xx from the boiler. This reservoir or steam chest is of about 86 cubic inches 

 capacity, and is provided with a drain pipe dd ; the steam enters about the middle of 

 its length, and the temperature in the chest is observed on a thermometer it, 

 standing in a tube act, containing oil. The steam from this chamber flows upwards 

 through the channel CO, leading from the centre of the upper cover to the orifice, the 



