OPTICS. 



OPTICS. 



Plate 

 (II.) Fig 



i .g. lo. NoAurnal 



{See AsTiioNOMicAL Instruments, Plate I. 



II.&IV. Fig. I— 4. RuJder 



r — 18. Plain Sailing 

 II. Fig. 19. Plain Sailing 



20 — 23. Parallel Sailing 

 24, 25. Mercator's Sailing 

 26 — 34. Great Circle Sailing 

 III. Fig. I, 2. Traverfe Sailing 

 2 — ^6. Current Sailing 

 I — 3. Naval Tadlics 

 [Referred lo as Naval Tactics, Plate I. fg. 



I — 5. Trigonometry 

 [Referred to as Trigonometry, Plate III. 



fs- 1—5) 



NOTATION. 



Plate of Arithmetical Charafters 

 [See Mifcellany, Plate l.fg. 7.) 



OIL MILL. 



Smeaton's Oil Mill 



1. Plan 



2. Elevation 



OPTICS. 



I. Fig. I. Aberration 

 2 — 4. Angle 



5. Burrouglis's Machine, Perfpeftive View 

 [Referred to as Plate II. fg. 4, 5.) 

 13. Altitude 

 [See Plate IV. Jg. II.) 

 II. Fig. I — 3. Parker's Burning Lens 



4, 5. Burroughs's Machine 

 [See Plate I. fg. ^.) 



III. ■ Fig. I — 7. Camera Obfcura 



IV. Fig. I, 2. Catoptric Ciftula 



2* — 4. Dioptrics 



5, 6. Difperfion of Light 



8. Focus 



[Referred to as Plate V. _/^. 2.) 



9. Looking Glafs 

 [Referred to as Plate IX. Jg. 10.) 



10—13. Shadow 

 14—16. Vifible 

 17. Vifion 

 V.&VI. Grinding, &c. 



(V.) Fig. I. Virtual Focus 

 2. Eye 

 2. Focus 



[See Plate lY.fg. 8.) 

 3 — ?• Grinding Machine 

 (VI.) Fig. 5 — II. Lens 



VI. Fig. I. Helioftata 



2. Bed of Hones 



3. Horopter 



4. RefraAion 

 [Thufgure is not numlered) 



VII. Fig. 1 — 12. Lens 



Plate 

 VIII. 

 IX. 



X. 



XI. 



XII. 

 XIII. 



XIV. 

 XV. 



XVI. 



XVII. 



XVIII. 



XIX. 

 XX. 



Fig. I — 12. Lens 

 Fig. !■ — 9. Light 



ID. Looking Glafs 



[See Plate IV. fg. 9.) 

 Fig. I — 3- Magic Lantern 



4. Apparent Magnitude 

 5 — II. Micrometer 



Micrometer 

 Fig. I. Dr. Maflvelyne's 

 2 — 4. Troughton's 



5. Herfchel's Lamp Micrometer 



6. Ditto, the arm enlarged 



7. 8. Ditto, the lamp open with the 



weight W 



9. Ditto, the lamp fhut 



[Fig. 7, 8, g. are not numbered on the Plate) 



10. Microfcope 



[The fame as Plate XII. _^. i.) 

 Fig. I — 12. Microfcope, Single 



Microfcopes 

 Fig. I. Marfhall's 



2. Culpepper's 



3, 4. Reflefting Microfcope 

 3". Dr. Smith's Ditto 



6 — 8. Solar Microfcope 

 [For Mirror, fee Plate XV.) 

 Compound Microfcope 



I — 4. Adams's 



5— II. B. Martin's 

 Fig. I. Incidence, Inclination 



2 — 18. Mirror 



18. Mufcas Volitantes 



19, 20. Centering Objeft Glafs 



21. Opera Glafs 



22. Optical Inequality 



23. 24. Parhelion 



[Referred to as Plate XVU.fg. 8, 9.) 

 Microfcope, [fee Plate XVI.) 

 Fig. I — 8. Improved Solar Microfcope 

 [This is referred to under the article MICROSCOPE 



as Optk:s, Plate XV.) 

 [For Opera Glafs, > Plate XV. fg. 21.) 

 Fig. I — 8. Optometer, &c. 



9. Optic Place 



10. Pencil of Rays 



[The reference to f.g. 1 1, under Place, in Optics, 

 Jhould be to Jig. 9. ) 



11. 12. Polyhedron 

 [Referred to as Jig. 12, 13) 



12. Polemofcope 



13. Polyoptrum 

 [Referred to as Jig. 14.) 



14. Refleftion 



15. Reflexibility 



[For Parhelion, fee Plate XV. Jig. 23, 24.) 



Rainbow, Refraftion 

 Fig. I — 9. Rainbow 



10 — 24. Refraftion of Light 

 Fig. I — 15. Refrangibility of Light 

 Fig. I — 4. Shadow 

 {See Optics, Plate IV. fg. 10 — 13.) 

 5 — 7. Vifible 

 ( See Plate IV. Jig. 1 4— 1 6. ) 



8. Vifion, theory of 

 [See Plate IV. Jg. 17.) 



