The principle of the Albion press, though not the precise mode, is shown in the Imperial, which is an improvement upon

it.

The bar-handle being pulled over, the levers A, straighten the lever B, which fills a hole in the frame of the press thus:

The straightening of this lever forces the platen down upon the face of the type. The platen is lifted again on the return of the barhandle by two springs attached to the inside of the cheeks of the press, CD, but not shown in the engraving.

The Columbian press is worked entirely with levers. The bar A being pulled, the rod B draws the elbow C inwards towards the cheek D, and thereby pulls down the head E. The head is not a fixed and immoveable part of the frame, as in other presses, but is a large lever, its fulcrum being the cheek I. The platen F is attached to the head by an iron bar H, and when the head is pulled down, the platen beneath this bar is forced down

upon the face of the type. There is another lever, K, attached to the head bearing the eagle above it. The head in descending pulls downward the short arm of this lever as the head rests on a fulcrum formed by the cheek D at d, and, in consequence, the opposite end, that is, M, bearing the eagle, is lifted upwards; this in falling draws the bar-handle back to its place of rest, lifts the platen, and raises the head.

lever are understood. For it is really nothing but a compound lever applied to printing; and, indeed, this may be said also of the Albion and Imperial presses, though they do not exhibit it so fully and clearly. It is known to every schoolboy, that an ounce weight placed on one end of a lever, may be made to balance a pound placed at the other end of the lever, simply by lengthening the distance of the small weight, and shortening the distance of the large weight, from the fulcrum or point on which the lever rests. But the power of the lever may be enormously increased by using a number of levers in connection with each other. For instance, let it be supposed that the three levers here delineated

are of the same length, the long arms of each 18 inches, and the short arms 1 inch. A pound weight placed at A would press the short arm against the long arm of the second lever, with a force of 18 lbs.; this force of 18 lbs. acting on the long arm of the second lever, would press down its short arm with a force of 324 lbs.; this force of 324 lbs. acting on the long arm of the third lever, would force up the short arm with a force of 5832 lbs. ! The rule is to multiply the weight by the length of the long arm of the lever, and the product is the

force it exerts on the short arm.

For the sake

of clearness we will give the result in a sum :—

The weight on the long arm of
the first lever -

Multiplied by the length of the

lever

The power with which the long
end of the second lever will be

forced up.

This multiplied by the length of

lbs.

1

the second lever

18

144

18

The power with which the long 324
arm of the second lever will be
forced down.

This multiplied by the length of

the third lever

18

2592

324

The weight which 1 lb. on the 5832 first lever will balance on the

third lever.

The levers by which the power of the Columbian press is obtained are much longer than those which we have just described, and