cut off with scissors, and the two coated surfaces are carefully brought into contact and pressed together, when they cohere very tenaciously. In order to secure perfect contact and cohesion, they are next submitted to heavy rolling pressure. It is necessary to remember that any want of cohesion will issue in blisters, which will mar in greater or less degree the effect of the finished picture. It is important, therefore, that this operation be performed with care. The coated surfaces should be preserved alike from dust and from contact with fingers, or anything which could impair the cohesion of the India-rubber surfaces. In bringing the tissue into contact with the India rubber coated paper, the tissue should be bent back, so that contact is first made with the middle of the print; the ends of the tissue being then allowed to fall after first contact. Shifting the position after the tissue has touched the paper is inadmissible; it must, therefore, be laid on straight. After being placed, the back of the tissue may be lightly rubbed with the hand or a pad, the rubbing being from the centre outwards. It is an advantage to prepare a stock of paper in advance, and to use it about an inch larger than the tissue, and to fold this upon itself, so as to form a double thickness half an inch wide. Several prints may be attached to one piece of paper.
The press used for this and subsequent operations, in Messrs. Mawson & Swan's establishment, is a powerful copper-plate press (by which a pressure of several tons can be applied), having a plate of polished steel on the bed of the press, whilst a piece of thick elastic felt is placed between the print and the roller, compensating for possible inequalities in the tissue, paper, etc, and securing perfect contact in every part of the paper and print. It is probable that the more inexpensive rolling machines might be applied to this purpose without disadvantage;
