Ch. VI] 



CLASS DEMONSTRATIONS 



193 



letters, etc., are then cut out and pasted on the drawing as described 

 above. This photographic paper is rather thick and will show a 

 white edge where it is cut. Blacken the white edges of the letters or 

 words with India ink after the letters are stuck in place (fig. 106). 



Fig. ii6 B. The Gothic Type in Fig. ii6 A. Reduced to One-half and to 

 One-fourth Natukal Size. 



(From Optic Projection). 



Class Demonstrations 

 § 305. Demonstration microscopes. — Ever since the microscope 

 was invented physicians and naturalists have made the greatest use 

 of it for demonstration purposes. It was a favorite expression of 

 the older writers that the instrument had created a new world of 

 the minute. Naturally in the beginning each person used the instru- 

 ment for himself as with the simple microscopes of Roger Bacon. 



