About half a mile before you come to Wilmington is Brandy-wine River, remarkable for its mills, no less than thirteen being built almost close to each other upon it. The water, just above the bridge which is thrown over it, comes tumbling down with great violence over a bed of rocks; and seats, at a very trifling expense, could be made for three times the number of mills already built. Vessels carrying 1,000 bushels of wheat can come close up to them, and by means of machinery their cargoes are received from, or delivered to them in a very expeditious manner. Among the mills, some are for flour, some for sawing of wood, and others for stone. The improvements which have been made in the machinery of the flour mills in America are very great. The chief of these consist in a new application of the screw, and the introduction of what are called elevators, the idea of which was evidently borrowed from the chain pump. The screw is made by sticking small thin pieces of board, about three inches long and two wide, into a cylinder, so as to form the spiral line. This screw is placed in a horizontal position, and by turning on its axis it forces wheat or flour from one end of a trough to the other. For instance, in the trough which receives the meal immediately coming from the stones, a screw of this kind is placed, by which the meal is forced on, to the distance of six or eight feet perhaps, into a reservoir; from thence, without any manual labour, it is conveyed to the very top of the mill by the elevators, which consist of a number of small buckets of the size of tea-cups, attached to a long band that goes round a wheel at the top, and another at the bottom of the mill. As the band revolves round the wheels, these buckets dip into the reservoir of wheat or flour below, and take their loads up to the top, where they empty themselves as they turn round the upper wheel. The elevators are inclosed in square wooden tubes, to prevent them from catching in any thing, and also to prevent dust. By means of these two simple contrivances no manual labour is required from the moment the wheat is taken to the mill till it is converted into flour, and ready to be packed, during the various processes of screening, grinding, sifting, &c. [Sidenote: MARYLAND.]