*576 



M I N T. 



PLATE 

 eccxcvn 



Fig. 1, 8. 



Fig. 3. 



Fig. S. 



--i g . 4. 



Mini. .06,856 of milled money, which latter must have been 

 ""Y"* executed subsequent to the succession of Charles II. 

 The operations of the mint were suspended on the 

 death of his predecessor, which the commissioners from 

 Scotland represented to Parliament, occasioned an ex- 

 treme scarcity of money, and it ceased to work a short 

 time subsequent to the union of the kingdoms, (c) 

 Description of Mr. Barton's New Machine for equalis- 

 ing the thickness of Slips of Metal for malting Coin. 

 Fig. 1. of Plate CCCXCVII. represents a side eleva- 

 tion of the machine as it would appenr when in action, 

 and Fig. 2. a horizontal plan of it. This machine ope- 

 rates in the same manner as wire drawing-machines, 

 viz. by drawing the slips of metal forcibly through an 

 oblong opening formed between two surfaces of har- 

 dened steel. The box or case which contains the 

 steel dies, and also the pinchers employed to hold 

 the metal and draw it through, are represented on a 

 larger scale in fig. 3, 4, and 5, on the plate. Fig. 3. 

 shews a section of the die-box, and elevation of the 

 pinchers. The dies are composed of two cylinders, , 

 b, made of steel ; they are rendered extremely hard 

 and very straight upon their surfaces, being highly 

 polished ; these cylinders are fitted into convex cavi- 

 ties formed in the pieces of metal A, B, and are re- 

 tained in their places by clamping pieces c, c pressing 

 against them, by which means the steel cylinders are 

 firmlysupported,andpreventedfrom bending during the 

 violent action of the metal while passing between them. 

 The pieces of metal A, B, are fitted into a box C of 

 cast iron, so as to bear flat against the bottom of the 

 same, and are secured by bars, e, e, screwed across the 

 front, as seen in Fig. 5. which represents a front view of 

 the box containing the dies, the lower piece B rests 

 upon the ends of three screws d, d, d, which pass 

 through the metal of the box C, whilst the upper piece 

 A is forced down by the action of a large screw D, 

 which has a toothed wheel N upon its uppermost end, 

 with a pinion and lever to turn it round by and adjust 

 the distance between the dies ; the screw D is furnish- 

 ed with a clamping nut^ to remove any shake which 

 might remain in the threads of the screw ; the pieces 

 A and B are confined sideways by small screws g, g, 

 pressing against them very forcibly ; h, h represent 

 two extending screws, which are introduced between 

 A and B to force them asunder, find bring them into 

 firtn contact with the ends of the screws D and d, d, d. 

 The box containing the dies is fixed at one end of a 

 long horizontal frame, as seen at C, Fig. 1. and strength- 

 ened by cast-iron brackets, i, Figs. I . and 2. The 

 frame is furnished with adjusting bearings, k, k, at 

 each end, to support two axes E and F, which have 

 wheels fixed upon them adapted to receive endless 

 chains of metal of the form seen at 1,1; which lie 

 in channels formed along the surface of the frame. 

 A large cog-wheel G is fixed upon the axis F, to give 

 motion to the endless chains ; this cog-wheel is turned 

 by a pinion H, fixed upon an axis m, extending across 

 the top of the frame, and working in bearings at each 

 end ; a cog-wheel I is fixed upon the axis m, and works 

 into the teeth of a pinion K, upon a second axis across 

 the frame, which also carries a drum-wheel L for giving 

 motion to the whole machine by an endless strap. Fig. 3. 

 and *. represent the pinchers which take hold of the slips 

 of metal and draw them through the dies. The two jaws 

 of the pinchers are united by a joint pin n, which pro- 

 jects on each side of the pinchers, and is furnished 

 with small wheels or rollers, o, o, Fig. 4. to run along 

 the edges of the channel formed upon the frame. In 

 order to receive the endless chains, p, p are two wheels 

 similar to o, o, but are fixed upon an axle which 

 passes through between the tails of the pinchers ; 



the axle of the wheels ;;, ;>. is attached to strong links 

 of iron a, q, the ends t of which arc formed like a hook 

 to take hold of the rounds of the endless chains so as 

 to draw the pinchers along with it ; the pinchers are 

 situated over the endless chains, and will run back- 

 wards or forwards upon their wheels. They are caused 

 to gripe the slips of metal firmly between their jaws 

 by the axle of the wheels p, p, acting between two in- 

 clined planes formed upon the insides of their tails. 

 The links q, q are furnished with a weight r, which 

 operates to raise the hooked part t above the links of 

 the endless chains, whenever the strain upon the pin- 

 chers ceases by the slip of metal having passed through 

 and out of the dies. The slips of metal to be operated 

 upon by the drawing machine, are first rendered thin- 

 ner at one end in order to introduce them between the 

 dies and between the jaws of the pinchers. This thin- 

 ning of the ends is effected by the machine repre- 

 sented at Fig. 6. in the plate ; it consists of a small pair Fiy. 6 

 of rollers mounted in an iron frame, similar to a rol- 

 ling-mil). The upper roller A is cylindrical, whilst B 

 is formed with three flat sides, leaving only portions 

 of the cylinder entire, between the flat sides, the dis- 

 tance between the centres of the rollers is regulated by 

 screws having wheels on their upper ends in the man- 

 ner described for the drawing dies C in Fig. 1, 2, &c. 

 The rollers have pinions upon their axes which cause 

 them to turn round together ; they are put in motion 

 by an endless strap passing round a drum, upon the 

 axis of which is a pinion working into the teeth of a 

 wheel fixed upon the axis of the lower roller B. 



The end of a slip of metal is presented between the 

 rollers whilst they are in motion, not on that side of 

 the roller which would operate to draw the slip in be- 

 tween them, as in rolling mills, but on the contrary 

 side, so that when one of the flat sides of the roller B 

 comes opposite the circumference of the roller A, an 

 opening is formed, through which the end of the slip 

 of metal is to he introduced, until it bears against the 

 fixed stop b, at the back of the rollers ; now as the 

 rollers turn round, the cylindrical portions come op- 

 posite, and press the metal between them, forcing it 

 outwards, rendering the part which has been intro- 

 duced between the rollers as thin as the space between 

 their cylindrical surfaces, which allows the end of the 

 slip of metal to be passed between the dies of the 

 drawing machine to be seized by the pinchers. 



In using the drawing-machine, a boy takes hold of 

 the handle s, (when the hook * is disengaged from the 

 endless chain) and moves them upon their wheels to- 

 wards the die-box C. This causes the jaws of the pin- Fig. 3. 

 chers to open by the two pins v, t>, which are fixed across 

 between the links q, acting upon inclined parts outside 

 of the pincher tails, as seen in Fig. 3. The pinchers are 

 pushed up so close to the die-box, that their jaws enter 

 the cavity w, which brings them near the dies, in order 

 to seize the end of the slip of metal introduced between 

 them. The boy now holds the handle s upon the top of 

 the pinchers fast, and with the other hand draws the 

 handle x, at the end of the link q backwards. This 

 closes the jaws and gripes the metal He then presses 

 down the handle x till the hook / seizes the endless chain 

 whilst in motion, and carries the pinchers and slip of me- 

 tal along with it ; when the whole length of the slip of 

 metal has passed through between the dies, the strain 

 upon the pinchers is suddenly relieved, which causes 

 the weight r to raise the hook t above the chain, and stop 

 their motion. The machine in the mint has two sets 

 of dies, and endless chains, as will appear from Fig. 2. 

 MIRACLES. See TESTIMONY. 

 MIRAGE. See OPTICS and REFRACTION. 

 MIRRORS. See KALEIDOSCOPE and OPTICS. 





