72

[Book I.

Anglo Saxon Grane.

any depth, since a diminution in the velocity of the wheel from a smallerpinion, is accompanied with an increase of the energy transmitted to theroller and vice versa.

The Greeks and Romans employed the wheei and pinion in several oftheir war engines, and in various other machinery. Part of a cog-wheelwas discovered in Pompeii . They probably were also employed, as inNo. 21, to raise water from deep wells, a purpose f'or which they havebeen long used in Europe. See Belidor , tom. ii, liv, 4. From some ex-periments made by Mr. Robertson Buchanan, it was ascei'tained that thelabor of a man in working a pump, turning a winch, ringing a bell, androwing a boat, might be represented respectively by the numbers, 100,167, 227, and 248 ) hence it appears that the eflect of a man’s labor inturning a windlass, is fifty per Cent, more than in working a pump in theordinary way by a lever.

As a man cannot, with effect, apply bisstrength conveniently to a crank that de-| / scribes a circle exceeding three or four feet

m / in diameter, another ancient contrivance

Bjj A-hfl [} enabled him to transmit it through a series of

Iw ; ' revolving levers, inserted into one or both

ends of the roller; and which extended to af i M ^ A greater distance from the centre than the

jo crank, as in the copper-plate printing press,

ff tj| the steering wheel of ships and steam ves-

il sels, and numerous other apparatus employed

_ in the arts. It was formerly used to raise

'cm— ^ater i n buckets from mines and wells,No. 22. Anglo Saxon Crane. and ev.en to work pumps : (cams being se-

cured to the roller, raised the piston rods in amanner similar to the common stamping mills.) Agricola has figured itas applied to both purposes. De Re Metallica, 118, 129, 141. No. 22,is an example of its application by the Anglo Saxons , from Strutt’s An-tiquities.

c*iA>AAAt AS

No. 23, Drum attached to a Windlass.

“ There cannot be a more expeditious way to raise water from a deepwell, than to make a large wheel, [drum] at the end of the winlace,that may be two or three times the diameter of the winlace, onwhich a smaller and longer rope may be wound, than that which raises