DIRECTIONS for placing the COPPER-PLATES to VOL. XVII. 
1. Frontifpiece —Optics 
2. Portrait of Sir Isaac Newton 
3. Nigella, Nitidula, and Nolana 
4. Man and Woman of Nootka Sound 
5. Map of the County of Norfolk 
6. North Pole. Dog, Sledge, Sec . of the ArCtic \ 
Highlanders - - i 
7. Map ot the County of Northampton 
S. Map ot the County of Northumberland 
9. Notoclea, Notonecta, and Notoxus, Infects 
10. Map ot the County of Nottingham 
11. Portrait of Dean Noweli, 
12. Numbers. Magic Squares, Circles, See . 
13. Numidia, Nycteria, and Nymphtea 
14. Ochna. Yellow-leaved Ochna 
15. CEnanthe, QEnothera, and CEstrus 
16. Oil-mill, by Mr. Smeaton 
17. Olax, from the Coaft of Coromandel 
18. Oi.denlandia, Ealt-India Madder 
19. Onchidium, Oniscus', Sec . 
20. Oxopordum, Opercularia, and Ophio- 7 
GLOSSUM - 5 
21. Ophicephalus and Ophidium 
tz. Ophrys, Plate I. Bird’s-neft Ophrys 
23. Ophrys, Plate II. Tway-hlade, and Mufk Ophrys 
14. Ophilia. Bally-coma from Coromandel 
25. Optics, Plate I. Reflection and Inflection of 7 
Light - - - - 5 
zS. --Plate II. Theory of Refraction 
l 7 - -Plate III. Phenomena of Lenfes 
-8. ■-Plate IV. Phenomena of Lenfes 
29.-Plate V. Theory of Reflection 
3°. --Plate VI. Theory of Vifion 
3 1 * •——— Plate VII. Phenomena of the Rain¬ 
bow, and of Cauftics 
to face the Title. 
page 30 
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Optics Plate VIII. Telefcopes 
--- Plate IX. Herfchel’s Telefcope 
■-Plate X. Single Microfcopes 
-Plate XI. Double, or Compound, 
Microfcopes 
-Plate XII. 
Solar and Lucernal Mi¬ 
crofcopes - 
-Plate XIII. Micrometers 
-Plate XIV. Photometers and Optometers 
-Plate XV. Kaleidofcopes 
— Plate XVI. Properties of Optical In- 
flruments 
-- Plate XVII. Imperfections of Optical 
Inftruments 
-Plate XVIII. PerfpeCtive 
-^ Plate XIX. PerfpeCtive 
Plate XX. PerlpeCtive Inftruments 
Orchis, Plate I. Butterfly and Meadow Orchis 
-Plate II. Marlh Orchis 
-Plate III. Spotted and Long-fpurred 
Orchis .... 
Origanum. Dittany of Crete, and Marjoram 
Oriolus, Plate I. Golden Oriole, and Neft 
•-—• Plate II. African Oriole, male and 
female - - ... 
Ormosia. The Scarlet Necklace-tree 
Ornithogalum, Plate I. Neapolitan Star of 
Bethlehem - 
—--Plate II. Milk-white Star of 
Bethlehem - 
Ornithology. The Parts of Birds 
Ornitrqphe. Saw-leaved Ornitrophe 
Orobanche. Tall and Indian Broom-rape 
Orobus. Wood Bitter Vetch, &c. 
599 
60S 
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616 
620 
624 
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707 
73 1 
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761 
ib. 
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782 
786 
J. and Adlard, Printers, 
Bartholomew Close. 
