BRAMAI l'S MACHINE, or PRESS FOR PRINT ING BANK NOTES. Contrary to our usual practice, we have been obliged to introduce a description of this ingenious machine under the name of its inventor. It was out of our power to obtain a drawing and de scription of it when we were engaged in that part of our work which contains the word BANK, and we have therefore thou.),-ht it more advisable to insert our account of it in this place, than to refer it to some more distant article, where the insertion of it would be equally inconsistent with our general plan.
In many other parts of our work we shall have occasion to direct the attention of the reader to the inventions of Mr Bramah, which are no less credit able to his genius, than they have been useful to so ciety. His improvements upon locks ; his rotatory engine for raising water; his hydrostatic press, .r plied to cranes, and to the sluices of canals ; his im provement on the steam engine ; his planing machine, for producing parallel surfaces on wood ; his method of cutting screws and turning spheres ; his equalising tool, or apparatus for turning cylinders at one opera tion ; his method of introducing steam into the up per coppers of Breweries ; his contrivance for lock ing carriages ; his improved pens, by which no part of the quill is lost ; and his new plug and sliding cocks ; will all come under notice in the course of this work.
It was formerly the custom in the Bank of Eng land to fill up the numbers and dates of their notes in writing till the year 1809, when the machine in vented by Mr Bramah was adopted for this purpose. By this contrivance, the numbers and dates were in serted not onit in a more uniform and elegant manner, but the labour was diminished to less than one-sixth of what it was before.
The copperplates, from which the words of the notes are printed, are double ; that is, they throw off two notes at a time upon one long piece of pa per. This piece of paper, containing two notes, is then put into the machine, which prints upon them the number and dates in such a manner, that the types change to the succeeding number, and that the whole operation is performed without any attention on the part of the clerk. If one of the notes, for example, is No. I, No. I, and the other on the same paper No. 201, No. 201, when these are printed the machine alters itself to No. 2, No. 2, and No. 202, N. 202 ; and in printing these, the types again change to No. 3, No. 3, and 203, 203. The date, and the word London, are cast in stereotype, and each machine is lurnished with one of these for each day in the year, and they of course are changed every clay.
The Bank of England have upwards of 40 of these machines the greater part of which arc in con stant use. It was formerly considered sufficient labour for each clerk to fill up with the number twice repeated, and date twice repeated, 400 notes per day ; but since the introduction of the machines, one clerk has printed 1300 double notes, which are equal to 2600 single ones ; for though in the ma chine the double notes do not require more labour than single ones, yet to fill np the blanks by writing, would occupy twice the time.
The mechanism by which this is effected is ex tremely ingenious, and the principle is not limited to the numbering of notes, but is equally appli cable to the purpose of printing any series of num 1.iers which require continual alteration. In Plate LXXVI. we have represented one of these machines, which is not, however, precisely the same as any of those in use, being only a single one, and adapted for printing one note at once ; but we have only to suppose it extended to twice the length, and furnish ed with a double set of types, in order to fit it for printing two notes at the same time. In Fig. 2.
of Plate LXXVI., a perspective view of this machine will be found, and a section of its parts at Fig. 1. in both of which the same letters of reference are employed. A solid piece of mahogany, A A, forms the base of the machine, and to this two iron plates B B are screwed, forming the sides of a box, the front of which is removed in Fig. 2. to exhibit the interior, and the back is concealed behind the mechanism. Across this box, an axis D is placed, having its pivots fined into sockets, which are fast ened in the sides of the frame, as is evident from the figure. This axis carries the tympan E, which gives the pressure to print off the note attached to it by screws ; and a lever F is also fixed to the axis, by which the operator forces clown the tympan. The move able types, in which the principal novelty of the in vention consists, are fitted into a series of brass circles, mounted upon an axis G, extending across the cen tre of the frame. These circles are sufficiently point ed out in the perspective view, by the numerals on the types fixed in them ; they are ten in number, ar ranged in two lots of five each. Each circle (shewn more plainly at I, Fig. 1.) is divided into 11 parts, and at each a rectangular notch is cut, to receive the types I, 2, 3, 4, 5, 6, 7, 8, 9, 0, and a blank type. Five of the circles, thus prepared, being placed side by side, upon a fixed axis, G, on which they revolve freely, are sufficient for printing any number less than 100,000 ; because, as the circles can be turned about on their axis independent of each other, it is obvious, that any combination of the above figures may be produced, by bringing them to the highest point of the circle, which is the situation in which they are placed when an impression is to be taken. This will be more easily understood, if we con sider that the brass plate, which covers up the circles, is put in its place, as represented in Fig. 1. at a. This brass plate has two apertures through it, to receive the two series of types which project up a little above its surface when at the highest. In Fig. 2. this plate is removed, to exhibit the interior mechanism. The circles are made to revolve by means of wheels H, upon an axis, called the back axis, parallel to the axis of the circles. The end of it is seen at I, Fig. 2. projecting through the frame, and it carries three of the wheels II, two of which are at the same distance apart as the two series of figure circles to NI hich they apply. The third wheel is placed at an intermedi ate distance between the other two, and is acted upon by a catch or pallet 6, Fig. 1. attached to the axis of the tympan, by means of a joint, in such a man ner, that it will strike against the highest tooth of the wheel H, and turn it round one tooth. When the handle is lifted up rather beyond the perpendi cular, where a stop d, Fig. 2. upon the axis, meeting a projection d, Fig. 1. on the cover of the box, prevents it from moving farther ; but when the handle is returned down into the position of Fig. I. the pal let, though it again meets the tooth of the wheel, gives way upon its joint, and passes by without mov ing the wheel. In this manner, it will be seen, that every time the handle is pressed down to take an im pression, in raising it up again, to place a fresh paper upon the tympan, the pallet moves the wheels H one tooth, and as the teeth of these wheels engage the teeth of the figure circles, a similar motion is communicated to them, bringing a fresh number be neath the tympan, ready for printing.