658 Report on the Trials of Implements at Reading. 
pressure, easily maintained the speed of 2500 revolutions per 
minute. The water-gauge test was not applied to this machine 
at a higher rate of speed than that of 2052 revolutions, but with 
that velocity 2*85 inches of water were displaced. 
The inlet to this fan is 8 inches in diameter. It is prolonged 
to within a short distance of the ground ; at the lower end the 
sides of the tube taper inwards, so that a tight joint is effected 
by inserting it in another tube ; the junction with the flue is 
made with a curved galvanized-iron pipe. 
This fan is intended to be used if required in connection with 
a series of stacks by means of fixed and permanent flues built 
in the ground. A very important feature in the fixed system is 
the damper which connects a particular stack with the exhaust- 
ing apparatus, or disconnects them. Mr. Phillips exhibited 
damper boxes with close-fitting slides, which are opened or 
closed by means of a handle rod which extends to the outside 
of the stack. These boxes (see Fig. 7), which are of cast iron, 
Fig. 7. — Improved Damper Boxes hy Charles D. Phillips, Engineering 
Worl-s, Neioport, Mon. 
Damper and Box fixed. 
are made with one, two, or three inlets, according to the positioi* 
they are required to occupy in connection with other flues. The 
special peculiarity of these boxes is that the interior is rounded 
