one finisher; one hundred and thirty-two (132) under-flat cards, arranged for single carding, at the rate of forty-five and a half pounds each per day; one hundred and twelve (112) Whitin combination cards at fifty-four pounds each per day; seventy-two (72) English combination cards with cylinders forty-five inches in diameter, and forty inches wide, at eightythree and a half pounds each per day, and united in sections by railways.

The cost of the various systems, including cards, card-clothing, lap and railway-heads, troughs, shafting, belting, floor space, and plant for motive power, would be about as follows:

240 top-flat cards

132 under-flat cards

112 Whitin combination cards

72 English combination cards

$70,800 00

56,500 00

54,500 00

52,000 00

The daily expenses of operating, including labor, estimated from the best data at my command, with power at fifty dollars per year for horse-power, interest on the investment at six per cent, and repairs and renewals at six per cent, would be for

or about eight and two-thirds mills per pound for the top-flat cards, and about six and one-third mills for each of the other kinds.

The cost of labor forms less than thirty per cent of the entire cost per day in any of the preceding estimates, and the interest on the investment and the allowance for depreciation form in every case more than fifty per cent; hence improvements in this class of machinery, which tend to reduce the cost of the plant, are of more importance than those which merely aim to lessen the cost of labor.

The relative importance of the items forming the cost of these different systems is not the same in all cases. In some cases the amount of room available may be the controlling element, in others the cost of power or labor, and in others the amount of invested capital. It would be impossible, at this time, to consider all the varying circumstances.

The amount of strippings and flyings removed from ordinary top-flat cards, when arranged for double carding, is probably about nine per cent, and from under-flat cards about seven per cent, the chief difference being in the amount of flyings from under the cylinder. The statements in regard to roller-carding, embodied in the report of the meeting of this Association, held in April, 1877, show a loss of from one and one-half to three per cent. The net loss from waste, on any cards, is reduced by the value of that which is removed. If the nine per cent of waste, estimated as made on top-flat cards, can be sold or used so as to be worth two-thirds of its cost, the net loss with this system will be reduced to three per cent. The same disposition of waste on under-flat cards would reduce the loss to two and one-third per cent. I have no data respecting the waste on combination cards, but I estimate the net loss at not over two per cent. If we credit to the roller-card the value of its waste, the net loss on this system will still be not much less than on the other systems, but the advantage of removing the waste by means of flats, where they are used, will be great in comparison. Mote collectors, many modifications of which exist, are efficient devices for removing fine leaf from the work. It would seem that without something of this kind a large number of flats are necessary for securing clean work. I do not know to what extent they can be substituted for flats.

The flat card is most generally used in this country, and on all grades of work. Roller-cards are used in England for export goods, for low numbers for the home trade, and for printing cloths. Top-flat cards, or combination cards, are used in England for fine numbers for the home trade.

We ought not to shut our eyes to the fact that systems of carding, which differ from that most commonly approved in this country, are claimed to do good work at two-thirds the cost of the ordinary method. If the more expensive system is capable of saving its extra cost in quality of stock used, or in value of work done, it will still hold its own, but not otherwise.

THE NUMBER OF CARDS REQUIRED.

The amount of work done per card varies greatly in different mills. The average quantities for various numbers of yarn, using top-flat cards, arranged for double carding, is probably

about as follows for each pair of cards, consisting of one breaker and one finisher:

It is an interesting coincidence that these quantities correspond very nearly with the quotients obtained by dividing 240 by the square roots of the numbers of yarn; or, in other words, they vary inversely as the square roots of the numbers.

In the following table the first column contains numbers of yarn, the second the square roots of the numbers, the third the quotients obtained by dividing 240 by the square roots of the numbers, and the last column the quantities ordinarily carded on top-flat cards arranged for double carding:

*

It will be seen that the numbers in the last two columns substantially agree. Extending this rule to higher numbers, and substituting one process of carding, followed by combing, in

place of double carding, we should have as the proportionate

I suppose that we cannot explain this rule on any mathematical principle, but that its coincidence with the average practice is due to the obvious propriety of decreasing the amounts carded less rapidly than the reduction in the weight of the yarn.

It is obviously less expensive for a mill, having a given number of spindles on fine yarns, to decrease the quantity done per card a given percentage below the quantities which have been named, than for a mill on coarse yarns to make a similar percentage of reduction. For example, suppose a mill of forty thousand spindles, on No. 13 yarn, were to decrease the work done per card by ten per cent below the amount given in the table, there would be required an addition of about thirty cards, while a mill of the same number of spindles on No. 50 yarn could make a corresponding reduction of ten per cent by adding only eight cards. For this reason, the tendency to overcrowd on coarse work is much greater than on fine work, not only in arranging new mills, but in adding spindles and looms in those already established.

DOUBLE OR SINGLE CARDING.

The proper way to approach this branch of the subject is to consider which system will, with a given number of cards of a given kind, produce the best result. We ought not to compare eighty cards arranged on one system with one hundred of the same kind arranged on the other. We shall simplify the discussion, if, for the present, we confine our attention to the ordinary thirty-six inch top-flat card. With one hundred cards, on which it is required to produce twenty-five hundred pounds per day, shall we put twenty-five pounds through each card, or shall we divide the cards into breakers and finishers, and put fifty pounds through each?

The cost of labor in the card-room will probably be less with the single than with the double system, but the only legitimate

saring will be the most of making the laps in the lip-tead and of transporting them in the braker to the finisher cards. This labor can be done for lew than half a mill a poin 1. more or less of which will be offset by the advantage of greater concentration of malvipbels ca the dialle system. A greater saving than this sometimes appears to result from the single proces, when, as compared with the diable system, fewer cards are used, and a less number of grinders, strippers, &c. are employed. Lit such a saving does not result from the system employed, but from the diminution in number of cards used.

More ends will be united at the railway-head, to form a sliver of a given weight, with the single than with the double process. If the weight of silver taken from the doffer were reduced in proportion to the amount carled, the number would be doubled. It is, however, impracticable to make the card-sliver hold together if greatly reduced in weight, and the reduction in product is obtained partly by reducing the weight of the sliver, and partly by reducing the speed of the doffer. The number of ends to each railway-head is therefore, with a given kind of card, usually somewhat larger for the single than for the double process, and the stopping of one card in a section is a less evil in the former than in the latter system.

The carding action between the teeth of the card is probably better with a thin sheet in single, than with a thick sheet in double, carding, and it is probably true that the wear and tear of card-clothing will be less in the single than in the double process.

An evil, the magnitude of which depends on the amount of care used in keeping the slivers in the breaker railway-troughs so distributed as to make a sheet of uniform thickness, results from the double process. So far as the action of the card is concerned, it is a greater evil to feed it with a striped lap, such as will be made when the ends from the breaker cards are not properly distributed in the troughs, than from a lap which varies in thickness in spots and irregularly, as the laps from pickers are liable to do. When a striped lap is fed to a card, the limit of good work is the amount that can be done where the lap is thickest, and not the average weight of the lap. The cylinder and tops of a card which has been fed with a striped lap soon become loaded in stripes, and, if the irregularity is great, nits will be formed at the thick places, and the teeth will be so