Upon the whole, experience has very clearly evinced, that large sums cannot be prudently expended upon ma chinery calculated for articles of mere fashion, and that the exercise of mechanical genius will always be better directed to provide for the actual wants and conveni ences, than to gratify the whims and caprices of mankind. In a relined state of society, ornamental arts must al ways exist; but the establishments for producing these ought ever to be calculated to meet those frequent stag nations of demand, to which they are peculiarly exposed. The power required to drive this machine being very small, and even that capable of great reduction, by ju dicious alteration, an expensive establishment of mill work, moved by power, is not by any means inherently necessary for the business. The regularity of motion, produced by machinery, is indeed desirable ; hut the attendant expellee is more than equivalent to any advan tage gained by its use. It is desirable that one'simple rotatory motion should direct the whole, but this might be easily given by the attendant's hand, in a way entirely Similar to what is practised in the incle loon). The nee dle frame is a very expensive part of the apparatus, and this, as well as the whole concomitant machinery, may be easily dispensed with. The pattern wheels, instead of being 18 inches in diameter, might be reduced to six .inches, with equal efficiency ; and a pattern might be carried to any extent by constructing them as spirals. It is also very practicable to make common sewing nee dles answer the purpose of the perforators, and those may be purchased for 3d. per hundred, whereas the former, with the sliders, Sec. cost upwards of 10 shillings. The quantity of work, upon a plan of this kind, might even be greatly increased, by working two, four, or six rows at once; and, at the same time, a machine might be constructed, by simplifying all its parts, certainly for not more than 8/. or 10/. and probably for much less. In such a state as this, the trade might easily revert to its natural and legitimate channel; for the expense being but small, the machines would soon become the pro perty of those who wrought with them. They might be made to occupy so little room, as to be placed easily in an ordinary sized dwelling-house, and the connection betw cen the employers and the employed might be ren der,d exactly similar to that which at present subsists in the weaving, stocking-weaving, and other branches of manufacture. The pattern wheels alone ought to be the manufactur?r's property, and these might be delivered with the goods, and returned when they were finished, like the wheels used in lappet weaving. A sketch of the eeneral principles of a machine of this kind, which embraces no one part of the patent granted for the for mer, will he found in Plate CXXXVII.
In this Plate, Fig. 6. represents a profile elevation of the machine, in .very part of which the most rigid at tention has been paid to simplicity and cheapness of con struction. T1,c frame work, which extends from the floor to the consists merely of two uptight posts of flay plank, repr. seined at A, the dimensions of which may be four inches by one. These posts, one of which only is visible, being firmly secured at top ano a single cross rail will be sufficient to connect nie,11, and may be of dimensions similar to the posts, and placed upon edge. In Fig. 6. it is not visible, but appear, tinctly at N, iu Fig. 7. The top of the posts nn.y be bolt ed to a cross piece or wood at II. nailed to the joi .ts above. The cloth frame of this machine appears at 1111, and from the curvature of its shape, the sieli s may be vet.) conveniently made of cast iron, and the cr•ss connections of well-seasoned wood. Of these cross connections, the
two of principal importance are the triangular pieces at KK ; for the top rail at II is merely uaed for the suspensary cords, and if these were attached to the tat s, both it and the bottom rail might probably he omitted, without any practical inconveniency. At I, I, are the two rollers for stretching the cloth, which may he made like those of any common tambour frame. In this machine the perforators are placed behind the 1 loth, upon the frame D. They may be made like common sewing needles, excepting that the eye being in the pain;, that end ought to be sharpened in finishing them, instead of being blunted to resist the thimble, as in the ordinary way. The other end may be filed into a triangular shape, like a glover's needle, and is to be fixed in a socket of tin like a stocking frame needle. This is effected by placing the needle in a mould, and pouring in the ti,1 while in a state of fusion. The shape, both of the nee dle and the socket, may he accurately seen in Fig. 8, to gether with a section of the bar upon which it is placed, and the means of securing it by a bolt and nut, so that any needle, if broken, injured, or worn out, may be changed at pleasure. The whip, or yarn, is placed upon a hollow tin cylinder, as in the former machine, and eve ry thread passes through the eye of the corresponding perforator. The motion given to the perforators is ex actly the converse of that in the former machine; for here the perforation is from behind, and the reciproca ting motion may either be given by wipers. or by two small cranks upon the ends of the shaft U, which is turn ed by the operator's hand. The form of the shaft ap pears in Figure 9. In the front of the cloth is a cross rail, to which is attached a frame carrying a number of perpendicular needles, one being correspondent to each perforator. When the perforators arc brought forward, these needles, by the rising of the frame, pass between the perforator and the thread, and thus form a loop, which remains until the perforators are withdrawn and return again, and so on. The proper regulation of this motion is the chief matter of nicety and difficulty in the machine. Copious remarks upon its nature, and the means or effecting it with accuracy, shall therefore be given in the proper place; as upon this rests the only difficulty of which this machine appears to be suscepti ble, and, at the same time, it is of such importance that this motion should be executed truly and steadily, that without that being accomplished all the rest would be nugatory and illusive. The pattern motion is, in this machine, to be given by two spiral worms, which may be six inches in diameter, or even less if desirable. These are represented in Figure 10, and some descrip tion of them may be necessary. They so far resemble in principle the transverse wheels of the former machine, that the figure of the pattern depends solely upon the form into which their rims are cut, and this depends upon the principles of calculation already described. Were a motion introduced to shift the contact of the frames at the end of each revolution, any number of ' ' wheels contiguous to each other, upon the same axis, would answer entirely the same purpose; but forming them as spirals will do equally well, and save some ad ditional machinery. In order to avoid the errors to which the ratchet was sometimes liable, on account of the in ertia, it is proposed to substitute in this machine an ob lique wheel, with what is generally termed by mechanics a double threaded endless screw. This being turned half a revolution for every shift, the whole shifts will be made with a precision, which may in every instance be relied upon.