O'Reilly — Ancient Water-milk, Native and Foreign. 73 



caulked and pitched in tlie same manner, asVitru\'ius says, as a vessel's 

 seams. This box extends over the breadth of the canal. Its other 

 extremity, which passes through the wall of the mill, is much narrowed, 

 and has but a small opening at its lower extremity, directed towards 

 the spokes or paddles of the horizontal wheel. The water precipitates 

 itself into this box, wliich presents a plane inclined at about 45°, and 

 finding its only outlet, this narrow opening, rushes out with a riolence 

 that can be easily conceived. In fact the accumulated weight of the 

 water increased in action by the height of the fall, added to its volume, 

 which becomes, as it were, doubled by the narrowing of the walls of 

 the canal, should give a very strong impulse to the jet as it escapes 

 from this sort of funnel, its action exercising itself entirely on the 

 spokes or buckets which it acts upon from the side, and which are 

 arranged horizontally, and hollowed out so as to receive normally this 

 jet, which must, therefore, cause the wheel to revolve with sufficient 

 rapidity, and, perhaps, with more than could be fui-nished by a compli- 

 cation of wheel-work. 



(p. 97). — "We had an opportunity of examining another mill, 

 wherein the same system of motive-power and the same mechanism 

 have been employed with slight modifications. 



At first sight they seem to offer few advantages, but yet fulfil the 

 intentions of the builders. The canal or watercoiu'se is raised several 

 feet above the level of the wheel; but the conduit into which the 

 water falls, instead of offering the form of a reversed pyramid and 

 being disposed diagonally, presents a frustum of cone and is jjlaced 

 vertically. 



The water enters it by a naiTOw orifice at the summit, and filling 

 the column — broad at its base — escapes from it by a tube which 

 penetrates it horizontally, and which is placed at the level of the 

 wheel. Moreover, instead of allowing the surplus supply, as in the 

 previous example, to run to waste, it is utilized by dividing the cm-rent 

 so as to make the water give motion to two wheels, thus twinned and 

 joined one to the other. With this object the water-coiu'se is enlarged 

 towards its extremity, and divided into two equal-sectioned channels 

 by a diaphragm, or division of thick planks, each fitted with a sluice, 

 and which are in connexion with the two cones into which the water 

 precipitates itself at the same time, thus putting in motion the double 

 mechanism. 



From this very complete description given by Castellan it will be 

 evident that the mill he speaks of is of precisely the same nature as 



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