358 PAPIiU MAKING. 



they take cure to apply two sheets of brown paper of an equal siee 

 to every handful. This brown paper, firm, solid, and already sized, 

 is of use to support the sheets. 



As soon as the paper is sized, it is the practice at some paper- 

 mills to carry it immediately to the drying.house, and hang it be. 

 fore it cools, sheet by sheet, on the cords. The paper, unless par. 

 ticular attention is paid to the lattices of the drying.house, is apt 

 to dry too fast, whereby a great part of the size goes off in eva- 

 poration : or, if too slow, it falls to the ground. The Dutch dry- 

 ing.houses are the best to prevent these inconveniences : bat the 

 exchange after the sizing, -which is generally practised in Holland, 

 is the best remedy. They begin this operation on the handfuls of 

 paper, either while they are still hot, or otherwise as they find it 

 convenient. But, after the exchange, they are careful to allow the 

 heaps to be altogether cold before they are submitted to the press. 

 Without this precaution the size would either be wholly squeezed out 

 by the press of the exchange, or the surface of the paper become very 

 irregular. It is of consequence that the paper, still warm from 

 the sizing, grows gradually firm, under the operation of the ex. 

 change, in proportion as it cools. By this method it receives that 

 varnish which is afterwards brought to perfection under the press, 

 and in which the excellence of the paper either for writing or draw- 

 ing chiefly consists. It is in consequence of the exchanging and 

 pressing that the Dutch paper is soft and equal ; and that the size 

 penetrates into the body of it, and is extended equally over its 

 surface. 



The exchange after the sizing ought to be conducted with the 

 greatest skill and attention, because the grain of the paper then re. 

 ceives impressions which can never be eradicated. When the sized 

 paper is also exchanged, it is possible to hang more sheets together 

 on the cores of the drying house. The paper dries better in this 

 condition, and the size is preserved without any sensible waste, be. 

 cause the sheets of paper mutually prevent the rapid operation of 

 the external air. And as the size has already penetrated into the 

 paper, and is fixed on the surface, the insensible progress of a well, 

 conducted drying.house renders all the good effects more perfect in 

 proportion as it is slowly dried. 



If to these considerations is added the damage done to the paper 

 in drying it immediately after the press of the sizing. room, whe- 

 ther it is done in raising the hairs by separating the sheets, or in 



