OF THE ALG.E GENERALLY. 



2. A tiny sieve, such as is sometimes suspended from 

 •the mouth of a teapot to intercept the minute portions of 

 the leaves. It must be of very fine wire, and provided 

 with a handle. Its use is to secure floating masses of 

 Desmidiacese, Limnochlids, &c. 



3. A common iron spoon is convenient for lifting with 

 care the upper layers of mud, where there is reason to 

 suspect the presence of Diatomaceas and Desmidiacese. 



4. Where Characeae are likely to be met with, or, indeed, 

 for dredging purposes generally, Caspary's rake is an 



Fig. 8. 



admirable instrument, fig. 8. It is made of iron, and is 

 of the following dimensions : — Length, a, b, ten inches ; 

 width, c, d, from the point of one tooth to the oj3posite 

 point, three and three-quarter inches; distance between the 

 points of the teeth c, e, three-quarters of an inch. The 

 handle, /, g, terminating in a ring^ to which a stout cord 

 may be attached, is five inches long. The weight of the 

 instrument must not be less than two or three pounds; 

 if lighter, it is apt to jump over slight obstacles at the 

 bottom of the water, and thereby miss the object to be 

 caught. The length of line, which should be about the 

 thickness of a finger, must of course be adapted to the 

 depth of the water. An Alpine lake frequently requires 

 as much as eighty or ninety feet. For convenience 



