174 



one or several delicate spider lines, which are 

 moved across the space to be measured by an 



Fig. 46. 



accurate screw of either 0.5 mm. or -^ inch pitch, 

 which has at its end a graduated disk divided in 

 1 oo or finer spaces, thus giving a definite value for 



Field of Large Filar Micrometer 

 showing cross hairs and recording comb. 



each space. An adapter is also provided for 

 attaching to the tube of microscope. 



