I I 



Fig. 37. VIEW OF THE MANGE INSECT OF THE HORSE, MAGNIFIED 150 TIMES IN ITS 

 LINEAR AND THEREFORE 22500 TIMES IN ITS SUPERFICIAL DIMENSIONS. 



MICROSCOPIC DRAWING & ENGRAVING. 



CHAPTEE I. 



1. Beautiful precision of the minute structure of natural objects. 2. 

 Cornea of a fly's eye. 3. Number of eyes of different insects. 

 4. Astonishing precision of artificial objects. 5. Demand for sucli 

 objects by Microscopists. 6. Classes of such, artificial objects. 7. 

 Microscopic scales. 8. Method of engraving them. 9. Measurement 

 of microscopic objects with them. 10. Their minuteness. 11. Scales 



LARDNER'S MUSEUM OF SCIENCE. B 49 



No. 67. 



