LIST OF ENGRAVINGS.

FigurePage
[1.]Representation of the diminution of the intensity of light.22
[2.]Illustrative of the refraction of light.43
[3.]Representing the angles of incidence and refraction.44
[4.]The refraction of the atmosphere.51
[5.]Various forms of lenses.65
[6,][7,] [8.] Parallel, converging, and diverging rays.66
[9,][10,] [11.] Passage of parallel, diverging, and converging rays through convex lenses.67
[12.]Passage of parallel rays through concave lenses.69
[13.]Images formed by convex lenses.71
[14.]Angle of incidence and reflection.83
[15.]Images as reflected from a plane mirror.84
[16.]Illustrative of reflections from a plane mirror.85
[17.]Shewing how the image in a plane mirror is twice the length of the object.86
[18.]Reflection from concave mirrors.87
[19.]Reflection from convex mirrors.89
[20.]Parallel rays as reflected from concave mirrors.91
[21.]Diverging rays as reflected from concave mirrors.91
[22.]Images formed before concave mirrors.93
[23.]Images formed behind concave mirrors.96
[24.]Illustrating the magnifying power of concave mirrors.97
[25.]Inverted images formed in the front of concave mirrors.98
[26.]Illustrative of deceptions produced by concave mirrors.100
[27,][28.] Experiment with a bottle half filled with water.101
[29.]Effect of extraordinary refraction on ships at sea.109
[30.]Experiment for illustrating the causes of uncommon refraction.117
[31.]Prismatic spectrum.127
[32.]Different foci of coloured rays in convex lenses.129
[33.]Experiment to show the different foci of red and violet rays.129
[34.]Illustrative of the prismatic colours.136
[35.]Explanatory of refraction and reflection from drops of rain.147
[36.]Explanatory of the rainbow.149
[37.]Images of objects formed in a dark chamber.187
[38.]The revolving Camera Obscura.194
[39,][40.] The portable Camera Obscura.195, 196
[40,]*[41,] [42.] Illustrative of the angle of vision, and the apparent magnitude of objects.206, 207, 208
[43.]The Galilean telescope.215
[44.]The astronomical telescope.218
[45,][46.] The aerial refracting telescope.226
[47.]The common refracting telescope.228
[48,][49,] [50.] Manner in which the rays of light are refracted in telescopes.231
[51.]Telescope with a single lens.234
[52.]Illustrative of spherical aberration.236
[53.]Illustrative of the principle of achromatic telescopes.241
[54,][55.] Double and treble achromatic object-glass.242
[57.]Common stand for achromatic telescopes.260
[58.]Equatorial stand for achromatic telescopes.262
[59.]Dollond’s stand for achromatic telescopes.264
[60.]Blair’s fluid achromatic object-glass.271
[61.]Barlow’s fluid telescope.274
[62,][63,] [64,] [65,] [66.] Various forms of reflecting telescopes.288
[67.]Gregorian reflecting telescope.293
[69.]The aerial reflector.313
[70.]Front view of the aerial reflector.314
[71.]Construction of large reflecting telescope.322
[72.]Reflecting telescope with a single mirror.332
[73.]Huygenian eye-piece.336
[74.]Ramsden’s eye-piece.339
[75,][76.] Combination of lenses for achromatic eye-pieces.340
[77,][78.] Diagonal eye-pieces.344, 345
[79.]Terrestrial eye-piece with four lenses.349
[80.]Eye-piece of an old Dutch achromatic telescope.356
[81.]Pancratic eye-piece.359
[82.]Manner of exhibiting the solar spots.384
[84.]Mode of measuring distances from one station.430
[85.]Cavallo’s micrometer.446
[86.]The equatorial telescope, or portable observatory.455
[87.]Figure to illustrate the principle of the quadrant.491
[88.]The astronomical quadrant.493
[89.]The astronomical circle.496
[90.]The transit instrument.502
[91.]Plan of a private observatory.511
[92.]Rotatory dome for an observatory.513
[93.]Wheel-work of a planetarium.521
[94.]Perspective view of a planetarium.522
[95.]Apparatus for exhibiting the retrograde motions of the planets.525
[96.]Section of the wheel-work of Dr. Henderson’s planetarium.528
[97.]Thirteen views of the supposed form of Saturn’s ring.539
[98.]Earl of Rosse’s Great Telescope.559
[99.]Section of the machinery connected with the telescope.560
[100.]Perspective view of the author’s observatory—to front the title.

THE
PRACTICAL ASTRONOMER.

PART I.
ON LIGHT.