screens should go round under the likerin, from the fluted rollers, and extend from thence under the main cylinder, and around this cylinder, and between it and the doffer. It can be safely taken thus far without coming in contact with the doffer; here it should be doubled over, and not present a raw edge between the two cylinders. The end, when neatly doubled over, should descend at least five or six inches. The screen must be a full inch distant from the doffer at every point; for, if any waste or cotton catches on it, sticks, and rubs against the doffer, it makes a very ugly appearance in the stuff coming off the doffer.

LENGTH OF SCREEN.

Screens are generally made of zinc, all in one piece, and as wide as the framing of the card. About eighteen inches in length of the space under the cylinder, and four inches under the likerin, the full width must be punched regularly with half-inch holes, at the distance of about half an inch apart, to allow the sand and dirt to fall through. The screen should be placed at the distance of about three-sixteenths of an inch from the card-teeth of the likerin and cylinder, very accurately put up to fit the circumference of the circles, and so firmly fixed that it will not be liable to be easily moved when anything is being done about the cards. The screen should be connected altogether with the frame-work of the card, and not be in any manner attached to the floor.

NUMBER OF HOLES.

For thirty inch cards the screen will require to be about thirty-six inches wide, and should contain forty holes in this

width; aud in the eighteen inches under the centre. in the direction from the likerin to the doffer, there should be at least twenty holes in the width: this will make 800 holes under the main cylinder. Perhaps one foot would be enough in this last direction. If we put twelve holes in this one foot by three feet, it will make 480 holes; 200 holes are sufficient under the centre of the likerin.

USE OF SCREENS.

There is a diversity of opinion among good cotton-spinners and carders, as to the utility of screens. Experience shows that they have a tendency to make the cards dull in a short time, and to cause seeds and large motes to stick in the teeth, if the cotton is dirty. Notwithstanding this, screens effect a great saving of cotton and labour. A card, thirty inches, wide, turning off. about sixty-two pounds of cotton per day, will, without a screen, produce flyings amounting to not less than twelve pounds per week, and, if an inferior kind of cotton be used, it will amount to nearly eighteen pounds. At any rate, if we consider the cotton to be fair, it will amount to twelve pounds. It is true that a considerable portion of this cotton would be fit to mix into filling, coarse yarn, &c.; but then what a waste of time and labour in picking, sorting, and mixing, what dirt and confusion is occasioned in the cardroom, taking out these flyings twice every day from under all the cards, in addition to other inconveniences. But when screens are used, and well fixed, a card will not make more than three pounds of flyings per week, instead of twelve pounds, which, in twenty-eight cards, amounts to 336 pounds of cotton. By the screen system, the loss would be eightyfour pounds. There are thus 252 pounds of good cotton saved

per week, on twenty-eight cards. These are positive practical facts. The last waste may be packed into a bag without any further trouble, and will be worth from two to three cents per pound. The amount of 252 pounds per week in favour of the screens will amount to 13,104 pounds per annum, which, at 12 cents per pound, would be worth the sum of $1633. So much in favour of the screens, which should be a conclusive recommendation of them.

ADVANTAGES OF SCREENS.

Some persons object to the screens, and say that they make the yarn dirty and weak. But if the cylinders and top cards are kept properly stripped and ground, the screens will work well. The advantage of the screens is, that the greater part of the fibres, which would, otherwise, fly off the cylinders and lodge under the cards, are wrought up into yarn. This part of the cotton is quite as long and strong in the staple as the best of the stuff, and the shorter parts pass in by such a regular and imperceptible process, that the yarn is not weakened or injured by it. In the cards previously alluded to, the pulleys and crank-straps run inside of the frame and covers, and cause considerable quantities of cotton and waste to be thrown on the floor; this can be remedied by putting the straps on the outside.

When the screens do not give satisfaction, it is owing to their improper construction. The expense of fitting them up is very trifling, when compared with the benefits to be derived from them. Everything which effects a saving of labour and material, should be brought into use in these days of foreign competition and rivalry, if it proves to be worthy of a trial.

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TO CONNECT CARDS BY RAILROAD.

Railroads, as they are called, are in front of the cards; by these the slivers from six or twelve cards are all run along in a trough on a strap, and pass in the mean time through a series of rollers, placed together in the same manner as in a drawing-head. This improvement saves the labour of changing cans, is a saving of them, and also a saving of the floor at the same time. The whole of those ten or twelve card-slivers pass into one can, which is generally convenient to the drawingheads. These railroads have also a tendency to improve the work, so far as doubling together a number of ends is concerned, and thereby partly remedying any defects in the feeding, or irregularity of any single card. The fixtures and machinery of this improvement are of a complicated nature, and consequently liable to become deranged in some of its numerous parts, and prove troublesome. This may and does form a serious drawback to the advantages they possess.

As the principal use of these railroads is, to collect all the stuff produced by a number of cards into one can, they are certainly capable of being very much simplified. They are generally so constructed, that the stuff comes through the calender-rollers of the railroad at one end, and is of the same thickness when two or three of the cards are stopped, as if they were all in motion. To produce this desirable and very necessary effect, such a quantity of gearing, levers, cones, and clock-work machinery is required, as renders the whole system liable to get out of order. Any derangement of course materially affects the regularity of the stuff. When anything happens to any of the cards of the system, it causes a stoppage for the time being of all the cards attached to it, thereby stopping one-half or more of the machinery in a large room.

It is a wrong principle to have machinery of such a flimsy nature dependent on the watchfulness of a thoughtless, giddy boy or girl. If a piece of waste catches around a journal on two of the cards in such a system, it will stop six or twelve cards, with all the other machinery dependent on them, for a considerable length of time.

These railroads have now, however, arrived at such perfection, that nothing is wanting to bring them into general use, but care and attention on the part of the head carder. If he keeps the cards in good order, no difficulty will ever occur in the operations of the railroad. The improvement in the drawing-head which Jenks has patented, is perfectly secure. It admits of the stoppage of one, two or three cards, without disturbing the running cards, or the thickness of the lamina. As twelve cards are never usually connected in one system, nine may be set down as the highest number which should ever be so connected by railroad.

FACING CARDS.

The great improvements in card-grinding, introduced within the last twenty-five years, have abolished the destructive process of facing new cards, or old ones either; that is, by grinding them for several days against the teeth with a fast grinder. This has ceased to be a practice, and has been superseded by skill and practical knowledge. Many thousands of setts of good card covering have formerly been spoiled or greatly injured by this erroneous system of grinding, which was once deemed necessary to level the teeth, and bring them to an even surface. Formerly, before machinery was brought to such perfection as to cut and stick card-teeth in the leather, the points or surfaces of the teeth were not of such a uniform