MICROSCOPES. 231 



across : K is a magnifier, three of which are sent with this 

 microscope ; that with the largest aperture is the least mag- 

 nifier. They may be used singly, or either two, or alto- 

 gether, making thus seven different powers ; when all three 

 are used the power is very great : L is a box, containing a 

 concave and flat glass, for confining any small living insect 

 between, to be placed on the stage : H, a pair of forceps to 

 fit in the small hole in the stage to hold insects, &c., they are 

 opened by pressing the small studs between the thumb and 

 finger ; the other end has a small ivory cylinder to lay any 

 small object on : j, a needle in a handle, for turning an 

 object while under examination : G, a pair of tongs to take 

 up insects, &c. ; D and E, are ivory and glass plates to lay 

 any object on ; they fit into the stage : F is a slip of glass 

 used in examining animalculse, or the crystallization of salts, 

 &c. &c. Price, $10.00. 



Description of the Large Improved Compound Microscope. 

 (Fig. 752, next page.) A, B, c, represent the body of 

 the microscope, a middle glass and a double eye glass are 

 contained in a tube which slides within the part A, B ; this 

 tube may be occasionally drawn out a little way to increase 

 the magnifying power ; the body slides up and down within 

 a short spring tube at D : F, is a flat plate or stage for lay- 

 ing objects on : G, is a concave mirror for reflecting the 

 light upwards through any transparent object on the stage 

 to the eye at A : E, is one of the magnifiers, six of which 

 belong to the microscope ; another is represented at p : H, 

 is a magnifier set in brass, it is to be held in the hand for 

 viewing any of the larger objects : i, is a convex lens set in 

 a frame, the pin of the arm, K, which holds it, fits into a 

 hole in the stage, it is used for condensing the light of the 

 sun or candle on opaque objects : L, is a flat ivory plate 

 fitted to the stage, one side black, the other white ; it is 

 used for laying opaque objects on, the white side for dark 

 colored objects, and vice versa : M, is a concave glass for 

 holding fluids ; a flat glass is also sent in the box, both 

 fitted to the stage : N, is a brass box with a flat glass bot- 

 tom for fluids ; very useful for aquatic objects, as it will 

 hold more than the concave glass : o, is an insect box, small 

 living insects are confined therein between a concave and a 

 flat glass : Q, is a needle fixed in a wood handle, it serves 

 for turning about any object on the stage while under exam- 



