[ 728 ] 
The model of a machine for this purpofe is com- 
pofed of four wheels of different fizes, two clicks, 
three pinions, and a fly ; which is put into motion 
by the part of a wheel fixed to the arch of the lever 
of the fire-engine. 
The wheel, which is turned by the lever, or rather 
moved up and down by it, is loofe on its arbor ; and 
likewife one of the rochets, and the wheel next to it. 
The outfide rochet and outfide wheel are fixed on 
the arbor. 
There are two pinion-wheels fixed on the arbor; 
one on each fide, near the edge of the wheel moved 
by the lever, which turns them. 
There are alfo two clicks; one fixed to the great 
wheel, the other to the frame. Thefe exclufive of 
the wheel that moves the fly. 
The effedl is, When the lever moves the wheel 
downwards, its click forces the rochet fixed on the 
arbor to move along with it, and the other wheels 
the fame way. When it moves upwards, the click 
fixed on the frame flops the larger rochet, and the 
wheel next to it, which are pinned together. This 
wheel being flopped, and the great wheel carried 
upwards by the lever, the pinion towards the edge 
of the great wheel is forced round it, and moves 
the pinion on the other fide the great wheel ; which 
pinion moves the wheel fixed on the arbor, the con- 
trary way to the great wheel, which is carried up- 
wards by the lever. By which means, the arbor it 
conflantly turned the fame way, when the lever of the 
fire-engine is moved either upwards, or downwards. 
Upon the arbor there is alfo another great wheel 
fixed, which turns a pinion : on the arbor of which 
pinion 
