ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



795 



0"2 mm. The centimetres are numbered with large fig\ires and the 

 millimetres by microscopic figures from to 9. The approximate 

 position of the Microscope is read off by a pointer. One of the 

 smaller figures is always in the field of the view, which is 1 • 5 mm. 

 in diameter. At Hs a micrometer which can be rotated in azimuth. 



Fig. 125. 



Its five divisions coincide with one of the scale as seen through the 

 Microscope, and each is therefore equal to a fifth of 0*2 mm. or 

 0' 04 mm. The divisions are preferably inclined, as shown in fig. 125. 

 The reading in this case is 4*93G mm. as the last lino of the micro- 

 meter (reading from right to left owing to the inversion of the image) 

 is 3"4; divisions from the 4" 8 mm. jwint of the scale. As each 

 division is 0'04 mm., 3' 4 of these divisions = 0'13G mm. The 



3 G 2 



