ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 798 



MICROSCOPY, 

 a. Instruments, Accessories, &c. 



Albertotti's Micrometer Microscope.* — Dr. G. Albcrtotti, jun., 

 Las designed the instrument shown in fig. 123, for the purpose of 

 measuring microscopic objects more satisfactorily than can be done 

 with either eye-piece or stage micrometer. 



Fig. 123. 



If the diverging plates of Helmholtz's ophthalmometer are inter- 

 posed between the eye-piece and objective of a compound Microscope 

 in such a way that the axis of the plates is at right angles to the 

 axis of the Microscope, the effect of the plates on the apparent 



♦ Ann. (li OUalmologia, xi. (1882) pp. 29-30 (I pi.). 

 Scr. 2.— Vol. IV. 3 G 



