Part 1 — PREFACE
Reading edition
TO
THE FIFTH EDITION
The first edition of this work was written by my father, the late Mr. Lewis Wright, and was published in 1890.
The reception that it received testified to the fact that it met a long-felt want, and successive editions were published in 1895, 1901, and 1906.
My father, unfortunately, met his death in a railway accident in 1905, and the corrections and additions to the last edition, which had been to a certain extent prepared by him, were completed and written by myself, and the work as published then was again reprinted in 1911.
As the original text is now thirty years old, it has seemed better entirely to re-write the whole book rather than make fresh revisions, the more so as the last ten years have seen great advances in the science of Lantern Projection, and especially in the developments of Acetylene and Electric Lighting.
It has also seemed best at the present juncture to issue the book in two parts, the first dealing with the Projection of Lantern Slides only, and the second with the Demonstration of Opaque and Microscopic Objects, Scientific Phenomena and accessory apparatus, including Cinematograph Projection.
It must of necessity be many months before this second volume can be produced, for the simple reason that Optical Instrument Makers have as yet hardly had time to turn round after the war and produce their new models, and therefore any such book written now could do little more than describe apparatus that was on the market prior to 1914.
The present work, therefore, deals solely with the exhibition of Lantern Slides in the Optical Lantern, and as such I trust will be found of value to Schoolmasters, Social Workers, Lecturers, and, in fact, to all who use the lantern as a means of illustration.
RUSSELL S. WRIGHT. January 1920.
CONTENTS
CHAPTER PAGE
I. Introductory 1
II. The Illuminant 3
III. Paraffin-oil Lamps, Incandescent Gas and Spirit Burners 6
IV. The Acetylene Light 11
V. Limelight and the Acetylene Blast 16
VI. The Electric Light 39
VII. The Optical System of a Lantern 57
VIII. The Body of the Lantern 70
IX. Lantern Boxes, Stands, Reading Lamps, etc. 76
X. Screens and Screen Stands 79
XI. The Practical Manipulation of a Lantern 82
ILLUSTRATIONS
FIG. PAGE
1. Oil Lamp 6
2. Inverted Incandescent Lamp 8
3. Methylated Spirit Burner 9
4. Luna Lamp 10
5. The Moss Generator 12
6. The A.L. or 'Popular' Model 14
7. Acetylene Jet 15
8. Oxygen Cylinder in hemp cover 17
9. Double Lever Key 18
10. Fine Adjustment Valve 19
11. Construction of Beard's Regulator 20
12. Beard's Regulator 21
13. Regulator and Gauge 22
14. Gas-bags 24
15. 'Blow-through' Nozzles 25
16. 'Blow-through' Jet 25
17. Mixed Jet 27
18. Mixed Jet, Gwyer pattern 27
19. Mixing Chamber of Jet 28
20. 'Injector' Jet 30
21. 'Gridiron' Saturator 32
22. 'Pendant' Saturator 33
23. Fallot Air Blast 37
24. Fallot Air Blast, and Cylinder 37
25. Lime-tongs 39
26. Universal Hand-fed Arc Lamp 45
27. 46
28. Resistance 49
29. 'Scissors' Arc Lamp 51
30. 'Right-angled' Arc Lamp 52
31. 'Westminster' Arc Lamp 53
32. Arc Lamp with Induction Ring 56
33. The Optical System of a Lantern facing p. 57
33A. Optical System of Lantern 57
34. Optical System without Condenser 59
35. Action of Condenser 59
36. Forms of Condensers 60
37. Double Sliding Carrier 62
38. Beard's Dissolving Carrier 63
39. Focussing Action of Lens 64
40. Achromatic Lens 65
41. Petzval Combination 66
42. Hughes' Short-Range Lantern 71
43. Long-Range Lantern 72
44. Connections for a Bi-unial Lantern 73
45. Beard's Circulating Water Tank 75
46. Quadruple Lantern Stand 78
47. Reading Lamp 79
48. Roller Screen 80
49. Portable Screen Stand 81
50. Adjustment of the Light 84