PAPER MAKING. 335 



consist in preserving, and at the same time in highly softening, the 

 grain : the Dutch have carried this to the highest perfection. 



The exchange succeeds the operation last described. It is con. 

 ducted in a hall contiguous to the vat, supplied with several presses, 

 and with a long table. The workman arranges on this table the 

 paper, newly fabricated, into heaps ; each heap containing eight or 

 ten of those last under the press, kept separate by a woollen felt. 

 The press is large enough to receive two of them at once, placed 

 the one at the other's side. When the compression is judged suf- 

 ficient, the heaps of paper are carried back to the table, and the 

 whole turned sheet by sheet, in such a manner that the surface of 

 every sheet is exposed to a new one ; and in this situation they are 

 again brought under the press. It is in conducting these two ope- 

 rations to four or five times, or as often as the nature of the paper 

 requires, that the perfection of the Dutch plan consists. If the 

 stuff is fine, or the paper slender, the exchange is less frequently 

 repeated. In this operation it is necessary to alter the situation of 

 the heaps, with regard to one another, every time they are put un- 

 der the press ; and also, as the heaps are highest toward the middle, 

 to place small pieces of felt at the extremities, in order to bring 

 every part of them under an equal pressure. A single man, with 

 four or five presses, may exchange all the paper produced by two 

 vats, provided the previous pressing at the vats is well performed. 

 The work of the exchange generally lasts about two days on a given 

 quantity of paper. 



When the paper has undergone these operations, it is not only 

 softened on the surface, but better felted, and rendered more pliant 

 in the interior parts of the stuff. In short, a great part of the wa- 

 ter which it had imbibed in the operation of the vat is dissipated. 

 By the felting of paper, is understood the approximation of the 

 fibres of the stuff, and their adhering more closely together. The 

 paper is felted in proportion as the water escapes, and this effect is 

 produced by the management and reiterated action of the press. 

 Were it not for the gradual operation of the press, the paper would 

 be porous, and composed of filaments adhering closely together. 

 The superiority of the Dutch over the French paper depends al- 

 most entirely on this operation. 



If the sheets of paper are found to adhere together, it is a proof 

 that the business of the press has been badly conducted. To avoid 

 this inconveuienry, it is necessary to bring down the press at first 



