PAPER, MANUFACTURE OP 



487 



rior, with a number of spokes fixed transversely, nearly long enough to touch the 

 cage. By means of this contrivance, the machine being fixed upon an incline of some 

 inches to the foot, the rags, -which are put in at the top, have any remaining particles 

 of dust that may still adhere to them effectually beaten out by the time they reach 

 the bottom. 



The rags being thus far cleansed, have next to be boiled in an alkaline lye or 

 solution, made more or less strong as the rags are more or less coloured, the object 

 being to get rid of the remaining dirt and some of the colouring-matter. The pro- 

 portion is from 4 to 10 Ibs. of carbonate of soda with one-third of quicklime to 

 the cwt. of material. In this the rags are boiled for several hours, according to their 

 quality. 



The method generally adopted is that of placing the rags in large cylinders, which 

 are constantly, though slowly, revolving, thus causing the rags to be as frequently 

 turned over, and into which a jet of steam is cast with a pressure of something near 

 30 Ibs. to the square inch. 



After this process of cleansing, the rags are considered in a fit state to be torn or 

 macerated xintil they become reduced to a pulp, which was accomplished, some 

 fifty years since, by setting them to heat and ferment for many days in close 

 vessels, whereby in reality they underwent a species of putrefaction. Another 

 method subsequently employed was that of beating them by means of stamping-rods, 

 shod with iron, working in strong oak or stone mortars, and moved by water-wheel 

 machinery. So rude and ineffective, however, was this apparatus, that no fewer than 



1593 



40 pairs of stamps were required to operate a night and a day in preparing 1 cwt. 

 of material. At the present time the average weekly consumption of rags, at many 

 paper-mills, exceeds even 30 tons. The cylinder- or engine-mode of comminuting 

 rags into paper-pulp appears to have been invented in Holland, about the middle 

 of the last century, but received very little attention here for some years after- 

 wards. The accompanying figures (figs. 1593 and 1594) will serve to convey some 

 idea of the wonderful rapidity with which the work is at present accomplished. 

 No less than twelve tons per week can now be prepared by means of this simple 

 contrivance. The horizontal section (fig. 1594) represents an oblong cistern, of cast 

 iron, or wood lined with lead, into which the rags, with a sufficient quantity of 

 water, are received. It is divided by a partition, as shown (A), to regulate the 



