336 1 APER MAKING. 



gently, and by degrees with greater force, and to raise it as sue?, 

 drills as possible. By thu means the water, which is impelled to 

 the bid^s of the heaps, which has not yet escaped, returns to the 

 centre ; the sheets arc equally dry, and the operation is executed 

 without difficulty. 



According to the state of dryness in which the paper is found 

 when it comes from the apartment of the vat, it is either pressed 

 before or after the first exchange. The operation of the press 

 should be reiterated, and managed with great care ; o herwise, in 

 the soft state of the paper there is a danger that its j, rain and trans- 

 parency are totally destroyed. Another essential principle to the 

 success of the exchange is, that the grain of the piper is originally 

 well raised. For this purpose the wire cloth of the Dutch forms is 

 composed of a rounder wire than that used in France, by which 

 they gain the greatest degree of transparency, and are in no danger 

 of destroying the grain. Besides this, the Dutch take care to pro. 

 portion the wires, even where the forms are equal, to the thickness 

 of the paper. 



Almost every kind of paper is considerably improved by the ex. 

 change, and receives a degree of perfection which renders it more 

 agreeable in the use. But it is necessary to observe at the same 

 time, that all papers are not equally susceptible of this melioration ; 

 on the contrary, if the stuff is unequal, dry, or weakened by the 

 destruction of the fine parts, it acquires nothing of that lustre and 

 softness, and appearance of velvet, which the exchange gives to 

 stuff properly prepared. 



The sheds for drying the paper are in the neighbourhood of the 

 paper-mill, and are furnished with a vast number of cords, on which 

 they hang the sheets both before and after the sizing. The sheds 

 are surrounded with moveable lattices, to admit a quantity of air 

 sufficient for drying the paper. The cords of the shed are stretched 

 as much as possible; and the paper, four or five sheets of it toge. 

 ther, is placed on them by means of a wooden instrument resem- 

 bling a pick-axe. The principal difficulty in drying the paper, 

 consists in gradually admitting the external air, and in preventing 

 the cords from imbibing moisture. With regard to the first of 

 these, the Dutch use very low sheds, and construct their lattices 

 with great exactness. By this means the Dutch paper is dried 

 equally, and is extremely supple before the sizing. They prevent 

 the cords from imbibing the water by covering them with wax. 



