82 
GARDEN MECHANICS. 
through the flap valves and the air-vessels into the basin at each 
side of the pipe. The improved ram of Mr. Roe’s invention is 
composed of a square box, say fourteen inches long and three 
and a half inches square, one end of which is attached to a pipe 
leading from the head of water at the other end, being a valve called 
a pulse-valve. On the top, at about the centre of this box, an 
air-vessel is fixed ; between the square box and the air-vessel 
there is a valve, as well as another in the neck of the air-vessel, 
for supplying it with fresh air. The ram being ready for action, 
the water descends, being let down through the pipe, which 
causes the pulse-valve to close; the sudden close of the latter 
causes the water to retreat back again for a short space, which 
again permits the opening of the pulse-valve by the pressure of the 
atmosphere upon it. The water returning causes it again to close, 
it again retreats, and this constant motion causes the action of the 
ram. At each pulsation a small portion of water is admitted into 
the air-vessel, where the air being compressed by admission of 
the water, drives the latter up through a small pipe attached to 
the air-vessel to a height of one hundred, a hundred and fifty, or 
even three hundred feet, according the fall which can be ob¬ 
tained.” 
To afford an idea of the power of this improved engine, we 
may mention that one fixed at Lord Walsingham's, Merton Hall, 
with a fall of nine feet, projects the water to the top of the man¬ 
sion, a height of about fifty feet; another at Dumbleton Ilall, the 
seat of E. Holland, Esq., with a fall of twelve feet, raises the 
water fully a hundred and fifty feet; and a third at the Earl of 
Macclesfield’s, with a fall of six feet, throws it to the top of Sher- 
bourn Castle. 
It seems Mr. Roe’s principal object in the improvements 
effected by him, has been to simplify the construction of the ma¬ 
chine, so that in the event of an accident it may be easily repaired 
on the spot by any ordinary workman, without the trouble so 
justly complained of with the old apparatus, of sending it to town 
for the most trifling repairs, and this he has fully effected. 
