DRYING 159 



is then poured in — fresh or salt, as the case may be — 

 until it is just the least bit above the surface of the 

 piece of zinc. Now take a piece of white paper or card, 

 lay it with one surface on the zinc, and turn it over, 

 thoroughly wetting both sides. Then place the speci- 

 men to be mounted, carefully cleansed, upon the 

 paper ; with the forefinger of the left hand gently 

 depress the paper and zinc, until the specimen is float- 

 ing freely. With the right hand spread out the speci- 

 men upon the paper, using a pair of needles or a soft 

 brush to assist in the process. When finally spread 

 out, gradually release the pressure upon the zinc, 

 allowing it to rise and to drain off some of the water. 

 Then gently lift the zinc until the whole of the specimen 

 is out of the water. When the paper is fairly dry, but 

 before the alga has begun to show the effects, the speci- 

 men is to be placed upon a sheet of drying-paper, a 

 thin cloth is to be put over it, another drier upon that, 

 a specimen upon that, and so on. A flat board with 

 some stones makes a very good press ; better still is a 

 press consisting of two iron frames, with a network of 

 iron wire in the middle (Fig. 74), and each frame pro- 

 vided with four little hooks. These little hooks are 

 fastened together by four copper chains that can be 

 made shorter or longer, as circumstances require. 

 The chains must be fastened loosely, or only little 

 weight placed on the board in the beginning. The 

 specimens may be pressed more strongly the second 

 day. It is absolutely necessary to change the driers 

 every day, and it is better still to change them twice 

 a day in the beginning. 



For mounting the algae, white, unglazed, tough paper 

 is the best ; the driers must be of pretty thick drying 

 paper, or sheets of blotting paper. The cloth must be 

 a thin cloth or muslin, entirely free from starch. Most 



