Smithsonian Report, 1911.—Heaton. PLATE 3 
1. SECTION OF NATURAL RuBy, X 100. 2. SECTION OF ARTIFICIAL RUBY, X 10. 
3. SMALL ARTIFICIAL SAPPHIRE, MOUNTED IN 4. SECTION OF PEARL, X 50. 
CELL, X 10, SHOWING MINUTE BUBBLES. 
