INVERTEBEATA, CRYPTOGAMIA, MICROSCOPY, ETC. 



953 



tions to ordinary bristles, &c., is that after lifting a diatom, it is often 

 impossible to make it let go, on touching the place where one wishes to 

 deposit it, a difficulty rarely experienced with the glass hair. Although 

 somewhat brittle, yet with care it may be used a long while, and can 

 be easily replaced. * 



The material from which the selection is to be made is spread 

 on a piece of thin glass, and heated red hot, if it contains diatoms, 

 to burn out the organic matter ; this piece of glass is attached 

 to an ordinary glass slide, a little to the left of the centre ; and 

 to the right is put on the same slide the clean glass cover to 

 receive the picked out specimens, and directly under the centre of this 

 cover, on the under surface of the slide, a small ink dot, which can be 

 easily recognized though out of focus, when, having secured the object 

 on the end of the hair, the slide is pushed along to bring the cover 

 into view. In this way one can readily pass from the crude material 

 to the cover, without danger of detaching the specimen picked up. If 

 the specimens are to be mounted in balsam, it is necessary to put a 

 little thin solution of gelatine on the cover, and dry it. 



With regard to the principal part of the manipulation, the method 

 of taking off the object, just where and when we wish, and of arranging 

 into lines, circles, &c. ; this process is not his own as to idea ; he has 



Fig. 5. 



reason to believe it is, substantially, that used by the professional 

 preparers of these objects, though it has never before been made 

 known. Fig. 5 shows the Microscope with the finger attached at a, 

 and the hair just above the slide ; 6 is a glass tube having a bulb, and 



