96 ELEMENTS OF APPLIED MICROSCOPY. 
1719, who derived his idea from a study of the way in 
which wasps construct their nests from this material. 
The first step in paper-making is the treatment of the 
raw stock with some chemical in order to break it up, to 
dissolve the cementing gums, and to separate the cellulose, 
which is always the principal constituent of paper, in as 
pure a form as possible. The crude material is generally 
boiled with strong alkali under pressure, and then washed 
in a tank from which the waste water is removed by a 
revolving drum. Wood paper is also made by an acid 
process, the stock being treated with the bisulphites of 
lime and magnesia; and mechanical wood-pulp for a 
low grade of paper is prepared by simple attrition against 
stone surfaces without chemical action. 
After treatment in the boilers and washers, the paper- 
stock is bleached, and at this stage is known as “half- 
stuff.” It is next passed through the beaters, in which a 
wheel bearing knives breaks it up into a fine fibrous 
condition. Sizing, loading, coloring, and other auxiliary 
processes are accomplished in the beaters. Finally, the 
fully prepared pulp passes to the paper-machines, where 
it is spread in a thin sheet of running water over a 
moving endless belt of wire cloth. The fibrous material 
deposited in a fine and even layer passes on through 
felted rollers, which press out the last of the water and 
compact its texture. 
2. The Raw Materials of Paper.—Obviously paper 
might be made from any material which can be ground 
up to a fine fibrous pulp; and such bizarre substances 
as seaweeds, shavings, sawdust, corn-husks, cabbage- 
