660 Report on the Trials of Implements at Reading. 
Engineers' Trials of Exhaust Fans. 
On the 19th of July the Exhaust Fans, which have been 
previously described, were subjected to a trial of their capacity 
and a test of the power required to work them. Mr. Robert 
Neville (Steward of Engineering) and Mr. William E. Rich 
(acting for the Consulting Engineer), assisted by Mr. A. Carey 
(Assistant Engineer), conducted these trials in the Show-ground. 
Mr. Beaumont, C,E. (correspondent of ' The Engineer ' newspaper), 
assisted in taking the velocity of the air on entering or leaving 
the fan by means of one of Elliot Brothers' small air-meters, and 
the result of these observations is shown in the Table of Results 
(II.). The smaller dynamometer belonging to the Society was 
used in conjunction with a 4-horse-power vertical engine, made 
and exhibited by E. S. Hindley of Bourton. For the purpose of 
ascertaining the comparative exhausting power, a water-meter was 
employed. This instrument was a ^-inch glass tube, shaped like 
the letter JJ, one end of this tube was closed, and the other was 
connected by a flexible india-rubber tube with the air inlet of 
the fan. This inlet was closed by a blank flange through which 
the test tube passed. The gauge being graduated alike on both 
limbs, with the (o) zero point halfway up, water was poured in 
until it stood on both sides at zero. When the fan was worked, 
a partial vacuum was created, and the water rose on one side of 
the tube and fell to the same degree on the other. The dis- 
placement of water is read off as twice the rise in one limb, or 
rather the rise in one limb plus the fall in the other. It is 
necessary to explain that this test does not show what the fans 
would do when air from the stack could have free access, but it 
should give the comparative power of the fan to exhaust air. 
The annexed Table II., constructed by Mr. Rich, C.E., gives 
both the main features of the machines exhibited, and the 
results arrived at by these trials, and the following remarks 
explain some apparent inconsistencies. 
The discrepancies between tlie apparent manual powers required for working 
some of the fans on tlic stacks, and the powers required for working them in 
the dynamomctrical trials, Lave been explained as follows by the Consulting 
Engineer, Mr. Anderson, and his partner, Mr. Rich, who conducted the trials 
on the dynamometer for him. 
The hand dynamometer is one of the oldest and crudest of the Society's 
instruments, and certainly requires modernising and refining in its details and 
registering apparatus. Unfortunately, too, Mr. Rich had no opportunity of 
overhauling and adjusting it till the morning of the trial. However, with all 
its faults there is every reason to believe that the records published in the 
table, fairly represent the powers taken by the several fans rclatively to one 
another. 
It would have been much more satisfactory if the several fans could have 
