418 
REPORT— 1854. 
sure machinery was accordingly carried out at that dock, and the result 
afforded the first practical demonstration that the pressure of a column of 
water could be advantageously applied as a substitute for manual labour, 
not merely for the cranage of goods, but also to give safe and rapid effect to 
those mechanical operations which are necessary for passing ships through 
the entrances of docks. 
In all these instances the moving column of water was about 200 feet in 
elevation. At Newcastle and Liverpool the supply was derived from the 
pipes communicating with the town reservoirs, but at Grimsby a tower was 
built for supporting a tank into which water was pumped by a steam-engine, 
In the former cases, the fluctuation of pressure, consequent upon the variable 
draught from the pipes for the ordinary purposes of consumption, proved i 
serious disadvantage; but this objection had no existence at Grimsby, where 
the tank upon the tower furnished a separate source of power, undisturbed 
by any interfering conditions. Nothing could be more effectual for its pur¬ 
pose than this tower; but, in the natural course of improvement, I was sub¬ 
sequently led to the adoption of another form of artificial head, which 
possessed the advantage of being applicable, at a comparatively small cost, 
in all situations, and of lessening the size of the pipes and hydraulic m* - 
cliinery, by affording a pressure of greatly increased intensity. 
The apparatus thus substituted for a water tower I named “the Acrun"‘- 
icctor, from the circumstance of its accumulating the power exerted by tin 
engine in charging it. The accumulator is, in fact, a reservoir giving pn* 
sure by W in,lead of by elevation, and its use, like that of every provt^" 
° this kind, is to equalize the strain upon the engine in cases where 
quantity of power to be supplied is subject to great and sudden fluctuation^ 
1 he construction of the accumulator is exhibited in Plate I. fig. 1, and neei- 
but little explanation. It consists of a Inrge cast-iron cylinder, fitted wit* 
p unger, from which a loaded weight case is suspended, to give pressure to 1 
water injected by the engine. The load upon the plunger is usually sue' 1 ,, 
to produce a pressure in the cylinder equal to a column of 1500 
vation, and the apparatus is made sufficiently capacious to contain tibe 1 1 P 
quantity of water which can be drawn from it at once by the simyl to", 
action of all the hydraulic machines with which it is connected. w . 
e engine pumps more water into the accumulator than passes dire 
hydraulic machines, the loaded plunger rises and makes room in d' e *■), j. 
*T pu8; but when, on the other hand, the supply from the»«V ad 
less, tor the moment, than the quantity required, the plunger, with its 
escen s and makes up the deficiency out of store. . „ (be 
1™ i 1 a 9 cumu, «tor also serves as a regulator to the engine; for . in 
loaded plunger rises to a certain height, it begins to close a tbrottl - 
the stcam-p.pe, so as gradually to reduce the speed of the engine^ 
descent of the plunger again calls for an increased production ol F ]p51| 
lhe introduction of the accumulator, which took place in . the J hic b i< 
gave a great impulse to the extension of water-pressure machinery. 0 f 
rr ? *' are ? tly a PP l,ed > °r in course of being applied, to the P ^ s0 w 
aZS h n Ufih0Ul aU thc> » reat establishments in London, 2 p i,edit 
extensively 8 °*f eQt 1,1 Liver POol and other places. I I,ave ? jvjr.V 11 ^ 1, 
who ha?/ t ° 1 ra,lvva y purposes, chiefly under the direction of » j„ 
i ° Un ! a "“J ltitud e of cases, involving Jilting or tractl ^|LewP li- 
fled at th y ? ade availabl « J - Most of these applications are 
fhe loading? T 1,10 G r<j at Western Railway Company w ^ ^ 04 
of lnadn 1 f L UnIoadi ng of trucks, the hoisting into warehouses. » d ,^ 
of loaded trucks from one level to another, the moving of turn-table* 
