"Hitherto we have been referring to printed _sheets of paper_, which are either the size of double or single foolscap; the next object, therefore, is the conversion of these sheets into card-boards of the usual thickness. In France the card generally consists of two sheets of paper; but in England a more substantial article is demanded; it is generally four sheets thick, that is, the foreside and the back, and two inside leaves of an inferior description.
"In order to make a firm and smooth card, it is first necessary to obtain a paste of an equable well-mixed substance. A paste of this quality is produced from flour and water, mixed together, and heated to the boiling point, in a forty-gallon copper, by steam; which is made to pass into the interstices between the copper and an external casing of cast-iron, of the same shape as the boiler. By employing steam, instead of fire, the paste is not liable to burn, or adhere to the sides of the copper, and thus become deteriorated in its colour and quality.
"Previous to the commencement of pasting, it is necessary that the sheets be arranged in the order in which they are to be pasted. This operation is termed _mingling_. The _insides_, which are merely two sheets of paper pasted together, are placed between the foresides and backs, so that the paste may take them up without the possibility of error. A heap of paper so pasted will therefore uniformly consist of the foreside and back, between which, the inside, pasted on each side, is placed.
"The paste is laid on by means of a large brush, resembling the head of a hair-broom, with which the workman, by a series of systematic circular movements, distributes a thin coat. And by way of illustration of the long practice and manual dexterity which are necessary for perfection in even the simplest departments of art or labour, it may be worthy of notice that card-pasting is in itself a branch of labour, and that three or four years' practice is necessary to render the operator complete master of his business.
"These newly-pasted cards are then, in quantities of four or five reams at a time, subjected to the gradual but powerful pressure of a hydraulic press of one hundred tons, worked by a steam-engine. By this means the water in the paste exudes, and the air between the leaves is expelled, which would otherwise remain, and give the card a blistered appearance.