66 



THE MICROSCOPE 



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The motor is supplied with flexible connecting wire and 

 plug adapter, so that it can be connected with any ordinary 

 lamp fitting. 



The machine can be made to suit any voltage specified, and 



for direct or alternating current; in the latter case, the phase, 



cycle, etc., must be given. 



Pipettes. Pipettes (P'ig. 69) are small glass tubes of various shapes, and 



are useful for taking specimens out of fluid and transferring to the 



slip or object-holder 

 for examination. If 

 the upper end of 

 the tube be closed 

 with the finger, the 

 lower end can be 

 immersed in a fluid, 

 and the air within 

 the tube prevents 

 the entrance of the 

 liquid. On removal 

 of the finger from 

 the upper end, the 

 fluid enters the glass 

 tube, carrying with 

 it small bodies sus- 

 pended in it; by 

 replacing the finger, 

 the fluid will be re- 

 tained in the tube, 

 and thus transferred 

 to a slip, live box, 

 or compressor. Two 

 Instruments, or three ucedles, a pair of fine forceps, a pair of scissors, and a 

 scalpel are required for the manipulation of unmounted objects 

 before examination. For the collection of aquatic organisms 

 from either fresh or salt water, a collecting stick and net are 

 of great use. The net is made of fine bolting cloth, and is of a 

 conical shape with a glass bottle secured to its apex (Fig. 71). A 

 surface net that is towed behind a boat may be made in a similar 

 manner, and should be provided with a 

 smaU calico bag attached to its front edge 

 which may be fiUed with stones to enable 

 it to be towed along when sunk below the 

 surface of the water. 



Most of the free swimming fauna in 

 open water are near the surface during the 

 day, but there is often a great variation in the fauna to be 

 found at different levels. 



Fig. 



70. — Dissecting Instruments. 



Collecting 

 net. 



Fig. 71.— No. 3460, 

 Collecting Net. 



