110 THE MICROSCOPE. 



tube in or out. The object, if transparent, is illuminated 

 either by holding up the microscope towards a white cloud, 

 or other source of light, or by directing it towards a mirror 

 laid upon the table at such an angle as to reflect the light. 



Fig. Gl.Higliley's Pocket Microscope. 



If opaque, it is allowed to receive direct light through an 

 aperture in the outer tube. The extreme simplicity and 

 portability of the instrument which is only six inches 

 long constitutes its chief recommendation. 



Norman's (178, City Eoad) Universal Educational 

 Microscope consists of a well-finished stand with tripod 

 foot and two uprights, with axis for giving inclination to 

 the optical part. The body has quick and slow motions, 

 one Huyghenian eye-piece, three achromatic object-glasses, 

 viz. a i-inch dividing into J and 1 inch, all of fair de- 

 fining power and English made. The stage has a large 

 slid ing-piece, and a revolving wheel of diaphragms \ the 

 mirror has sliding and oblique motions for the better illu- 

 mination of the object under examination. The following 

 apparatus is also supplied with the instrument : a stand 

 condenser with adjustment, stage and hand forceps, live- 

 box or animalculae cage, a frog-plate for viewing the circu- 

 lation of the blood in the web of a frog's foot ; also three 

 good objects to test the different object-glasses, one hol- 

 lowed and two plain slips, some thin glass. The whole is 

 packed in a mahogany or walnut cabinet, with a drawer 

 for objects, lock and key, and sold for the small price of 

 3J. 5. 



24 first-class objects, suited for the object-glasses, are 

 supplied with this instrument for II. Is. 



Mr. E. Wheeler's (Holloway) well-made instruments de- 

 serve commendation and notice; they are carefully finished 

 and quite up to the modern standard. The full assorted 

 sets of objects which Mr. Wheeler supplies in a very neat 



