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.

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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

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