MICROSCOPIC DRAWING & ENGRAVING. 
CHAPTER X. 
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 such 
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. e 40 
No. 67. 
Fig. 37. —VIEW OF THE MANGE INSECT OF THE HORSE, MAGNIFIED 150 TIMES IN ITS 
LINEAR AND THEREFORE 22500 TIMES IN ITS SUPERFICIAL DIMENSIONS. 
