Manchester Meuioh's, Vo/. /m. (igoS), No. ^. 3 



attempt to obtain accurate readings within a few inches 

 of a fire purposely made up to the utmost capacity of the 

 chimney with a view of increasing the draught, was not 

 unaccompanied by some discomfort. 



The research was then transferred to the engineering 

 laboratories of the Manchester University, where a blower 

 for producing a blast for the forge fire, and driven fairly 

 steadily from the main line shaft, was available for 

 draught production. 



From this blower a pipe was taken to a convenient 

 bench and was arranged to discharge its blast horizontally. 

 At some distance in front of this the poker, which was 

 I" diameter, tapering down to ^J' in a length of 5 inches 

 at its upper end, was clamped at its lower end in a retort 

 stand, while a light wooden frame 6" square and divided 

 into h" squares by means of very fine wires, was clamped 

 at right angles to the poker and at any required position 

 relative to the latter. 



The Pitot tube was then used to explore the middle 

 point of each of these squares, the end of the tube nearest 

 the blast being held in the plane of the frame. In each 

 case the reading of the gauge was taken with the tube at 

 a given point first with and then without the poker in 

 position, and the direction of the tube was adjusted so as 

 to ascertain the maximum velocity at this point in each 

 case. 



The results of the experiments proved somewhat 

 startling, for although it was anticipated that the effect 

 of the poker would be marked, the magnitude of this 

 effect was most surprising. 



Details of these experiments are as follows : — 



The results have been entered in diagrammatical 

 form, the diagrams representing the portion of the frame 

 in the neighbourhood of the poker, the tip of the latter 



