208 MICROSCOPIC ILLUSTRATIONS. 



The erecting eye- piece must, of course, always be em- 

 ployed, by sliding it up and down in the body ; with 

 various objectives the power may be made gradually to 

 advance from a mere nothing- up to the l-20th of an inch 

 (which I conceive to be the utmost which can be used), 

 and still allow sufficient space between the object and 

 the object-glass for the anatomist to manage his imple- 

 ments, and to procure the necessary illumination. 



Mount the engiscope in the vertical position, and see 

 that the bar is locked fast in its front leg, to give the 

 utmost degree of stability ; place it on the tripod stool, 

 before recommended, with the front of the stage before 

 you, and the pillar next to the window — (a diagonal po- 

 sition for yourself and the instrument relative to it, will 

 be most convenient, to allow the light to fall freely on 

 your subject.) Use the single condenser, n, to furnish 

 your light, if necessary ; it may be moved round the 

 neck of the body, to suit your convenience. You may 

 also employ the lengthening piece,'/, if you please, which 

 will allow you to fix the stage on the pivot and sliding 

 socket, i, and give a lower position for it. If you use the 

 latter, see that it is clamped very fast, that it may not 

 give way with the weight of your hands. 



If you do not find it advisable to employ the false stage, 

 fig. 22, which procures a separate rest for the little 

 fingers, while the thumb and index finger operate, drop 

 the piece, fig. 27, into the aperture of the stage, and fix 

 it by turning it one quarter round. Then place the 

 piece of cork or wood, he. on which you dissect in the 



