PAPER MAKING. 341 



In the year 1801, a patent was granted to Mr. Koops, for ex. 

 tracting ink from printed paper, and restoring it to its original state. 

 His process varies little from that above described ; the paper be. 

 ing agitated in hot water to extract the size, and reduce it into a 

 pulp : next, the adhesion of the ink is to be removed by a caustic 

 alkali prepared of lime and potash, the quantities of which should 

 be proportioned to those of the paper. After discharging the ink, 

 he directs the pulp to be bleached by means of the oxygenated marine 

 acid, in the proportion of 10 or 12 gallons to 140Ibs. of the mate, 

 rial ; and when sufficiently whitened, it is re-manufactured in the 

 usual manner. According to the patentee's account, writing paper 

 does not require so large a proportion, if any, of the caustic alkali ; 

 but is bleached by confining it in a wooden box, rendered air tight ; 

 into which the acid gass is thrown directly from the retort wherein 

 it was produced. 



The staining or dyeing of paper is performed by applying, with 

 soft brushes, any of the colours used for tinging other substances, 

 after tempering them properly with size or gum. water. Should 

 the paper not be sufficiently hard to receive the tint without sinking, 

 it will Grst be necessary to size it, or to employ a larger proportion 

 of gum with the tinging matters. And if the paper is to be of an 

 uniform colour, the latter must be fixed by several thin coatings, 

 each being suffered to dry before another is applied j as the shade 

 will otherwise appear unequal. 



As writing paper is often imperfectly sized, in consequence of 

 which the ink is apt to sink, it has been recommended to dissolve 

 a small piece of Roman alum in a glass of pure water. This liquor 

 should be gently spread over the suspected part, with a soft sponge ; 

 and, after becoming dry, it may be safely used for writing. Should 

 there be any occasion to write on a printed book; or on paper that 

 is too fresh and moist, it will only be necessary to mix a little gum 

 with the ink. Lastly, in case any book or manuscript be stained 

 with oil, or grease, it has been directed to calcine and pulverize the 

 bones of sheep's trotters ; and to apply a small portion of the powder 

 to each side of the stain, which should be placed between two sheets 

 of white paper, and the whole submitted for the space of twelve 

 hours to the action of a press : if the stains do not disappear, the pro. 

 cess should be repeated in a warm place. 



[Pantolog. Annales de Chimie. 



z 3 



