THE GLASGOW MECHANICS' MAGAZINE. 304 On the rough side of a strap of leather, or on the undressed calf-skin binding of a book, rub a piece of tin, or a common pewter spoon, for half a minute, or till the leather become glossy with the metal. If the razor be passed over this leather about half a dozen times, it will acquire a finer edge than by any other method. As this fact may not be generally known, its insertion may be of use. Y. MISCELLANIES. to be placed during the preparation on a hot hearth or plate of heated iron, and the mixture stirred with a tobacco pipe. The cup to be placed in different parts of the sick-room. To determine whether Wheat Flour, or Bread, be adulterated with Chalk.-1. Mix with the flour to be tried, a little sulphuric acid: if chalk or whiting be present, an effervescence (arising from the discharge of the carbonic acid of the chalk) will take place; but if the flour be pure, no effervescence is produced.— 2. Pour boiling water on some slices of bread, and then pour into the water a little sulphuric acid; if there be any chalk in the bread, an effervescence will ensue, as before; but if none be in it no effervescence ensues.-Griffin's Chem. Rec. To detect Copper in Pickles or Green Tea. Put a few leaves of the tea, or some of the pickle cut small, into a phial, with two or three drachms of liquid ammonia, diluted with one half the quantity of water. Shake the phial : when, if the most minute portion of copper be present, the liquid will assume a fine blue colour.-Ib. Test for Jelly.-Let a grain of isinglass, glue, or any other gelatinous matter, be dissolved in a gobletful of water, and let a few drops of tincture of galls be added to the solution: the immediate product will be an abundant flocculent precipitate. This precipitate is a compound of the tan of the gall, and the pure gelatin of the jelly.-Ib. To determine whether water be hard or soft; that is, whether or not it be fit for domestic purposes. To a glassful of the water add a few drops of solution of soap in alcohol. If the water be pure, it will continue limpid; if it be impure, white flakes will be formed.-Ib. NOTICES TO CORRESPONDENTS. We wish that T. G. would recompose and condense his observations on the sounding line, as we really cannot make out the meaning of some of them.-We are obliged to Rusticus' for his last communication, which shall appear in due time; we beg leave to inform him that the proposer of the query respecting the point of meeting, having solved his case of the 19 miles, requests to know his address, so as to obtain his promised reward, by showing him the solution previous to its insertion in the Magazine.-Z. is partly superseded. Opifex,' D. L. M., J. D. C., and M. A., will be inserted.-W., of Lanark, and G. B., of Hamilton, under consideration. We are in arrears with some of our Correspondents, and must really crave their indulgence for a little.-We cannot see upon what principle A. would propose that the first proprietor of the stair should pay one-fifth of two-ninths; this is a strange mixture of parts; that, at one time, the stair should be considered as divided into 4 shares, and, at another time, into 5 shares; the solution given by Hutchesonus Frater' proceeds on the simple supposition, stated in the query, that the expense is to be paid in the proportion of 4 shares, and not in that of 5 shares; hence, it must appear absurd to alter the nature of the question, and then to assert that the solution is wrong. Published every Saturday, by W. R. M‘PHUN, 155, Trongate, Glasgow, to whom Communications (post paid) must be addressed. J. CURLL, PRINTER. MR. BUCHANAN'S PATENT CARDING MACHINERY. As I have distinguished all the The washer is screwed down by the nut 26, upon the spindle, until the friction produced by the leather, or intervening substance, has become sufficient to turn the shaft and machinery upon which it operates; but when any interruption is given to the radius bar, or any other part of the machinery operated upon, and to be afterwards described, the true turned and smooth surface of the wheel and washer, by sliding along the leather, or interposed substance, will permit such part of the machinery, as is exposed to danger by the obstruction, to remain at rest and without injury. This arrangement may therefore be considered merely as precautionary, and is not absolutely indispensable. 27, a screw wheel of 96 teeth, fixed upon the end of the crank shaft 28, and moved by the spiral, or screw, 23. 28, the crank shaft, extending across the machine, for the purpose of giving motion to, or traversing the radius bars 33. 29, 29, are the crank pins. One of these is fixed in the screw wheel 27; and the other in a circular piece of cast iron, placed upon the other end of the shaft. These pins are placed about four and a quarter inches from the centre of the shaft 28, and may be shifted nearer to, or farther from that centre, to adjust the sweep of the radius bars. 30, 30, are rack bars communicating motion to the radius bars 33. 31, 31, wheels fixed to the radius bars of 6 inches diameter, and 48 teeth. These wheels receive motion from the racks upon the rack bars 30, and communicate to the radius bars a traversing, or reciprocating motion, along the whole arch of top cards, from the point where it brushes the doffing cylinder, to that where the brush is cleaned by the needles. 32, 32, hasps and pullies, or rollers, which press upon the back of the rack bar, in order to keep the teeth of the rack properly pitched with those of the wheels upon which they operate. These hasps are fitted on to the bushes of the main cylinder, but remain loose, in order to accommodate the pullies to the va rying angles of the rack bars, in revolving round the centres of the crank shaft. 33, 33, are the radius bars, with balance weights below, to counterpoise them when at the extreme points of the range of motion. 34, 34, tops attached to the radius bars, and moveable at pleasure. 36, 36, arms fixed upon the moveable top, for conveying the revolving brush which cleans the top cards. 37, the revolving brush. (See fig. 1, No. XIX.) 38, pulley, 6 inches diameter, fixed on the end of the brush shaft, or axis. 39, the belt, or strap, which drives the brush. 40, 40, pullies of 6 inches diameter, fixed on the ends of the main cylinder axis. The pullies 40, by means of the crossed belt 39, drive the pulley 38, and consequently the brush 37, in the direction required for cleaning the top cards. By means of the apparatus described, each semirevolution of the crank 29, will move, or traverse the radius bars 33, and the revolving brush 37, from the doffing cylinder y, over the top cards, brushing and cleaning all which are turned up, until it reaches the opposite extremity of the arch, where it cleans itself upon the needles at 41. During the pause made, whilst the brush wheel is in contact with the doffing cylinder, and whilst the crank pins passing the centre give the least motion to the radius bar, that cylinder is also brushed and cleaned; and a similar pause taking place at the opposite extremity, affords time for cleaning the brush itself from the cotton, dust, and motts, by making its bristles pass through a moveable frame set with needles. In fig. 1. and 2. 48, 48, are arms for supporting the needle frame. 49 is the iron box which receives the strippings. 50, 50, are pins for supporting the iron box 49. These pins also form a rest for the imple ་ ments, or utensils, used for stripping, grinding, and brushing the main cylinder, when cleaning out the cotton, grinding the cards, and polishing with the brush. By removing the box 49, part of the sheet iron back lining may be folded down, which allows room for admission to the sheet cards of the main cylinder. The mode of turning up, and of returning the top cards to their working position, is as follows: 35, 35, &c. are pins, the tops of which form the hinges, or joints, upon which the top cards turn. The bodies of these pins are square, where they pass through the upper, and round where they pass through the under flanches of the framing. The round part is screwed, and by means of nuts above and below the under flanch, the front part of the top cards can be set nearer to, or farther from the cylinder. 52, 52, are pins screwed in the upper flanch, which, in a similar way, elevate, or depress the back of the top cards, one only is marked on each side; all the others being quite similar. These pins are so distinctly exhibited by the drawing, that a more special description seems to be quite unnecessary. 53, 53, is a piece of wood, placed across the frame, to support the top-card, No. 20, when turned over to be cleaned by the action of the revolving brush. In fig. 1. 54, 54, are the handles by which the top cards are lifted. 55 is the ratchet wheel of 51 teeth, or spaces, by which any number of top cards required, may be successively turned over, and exposed to the action of the cylindrical revolving brush. 56, 56, 56, 56, 56, are triangles screwed to the arms of the ratchet wheel 55. These points alternately elevate a sliding rod, placed in the inside of the radius bar. The motion of the radius bar raises the handle to the top of the groovo, where the top card, act- revolution of the ratchet wheel 55; and by placing more or fewer triangles upon its circumference, a greater or smaller number of top cards may be cleaned during each revolution. In drawing 2. 65 is a toothed arm, or rack bar, attached to the radius bar 33, and 66, 66, &c. are 18 semi-wheels, fixed upon the axis of the top cards. By means of these semi-wheels, which come in contact with the rack bar 65, when the top card is turned over; each top card (19 and 20 excepted) is returned to its working position, so soon as it has been cleaned by the revolving brush. The tops 19 and 20, which have no semi-wheels, and are placed beyond the reach of the rack bar 65, are returned into their working positions immediately after being cleaned by the return of the radius bar and the ascent of the handle through the groove 59, and its descent through 60, as already described, &c. &c. Glasgow, 28th March, 1824. ON THE CONSTRUCTION OF THE THERMOMETER. SOME precautions must also be It is necessary also to heat the tube, to a very considerable degree, before introducing it into the mercury, that the water, which has been allowed to enter while blow ing the bulb, if it has been done |