ILLUSTBATIONS.

PHOTOGRAPHS by RUTHEREURD.*

First Quarter, Feb. 27, 1871 ... ... . Frontispiece

Full Moon, May 14, 1870, 16h. 4m. 10s.

Sid. Time . To facep. 214

Third Quarter, Sept. 16, 1870, lh. 49m. Os.

Sid. Time. . „ 230

PLATES.

Plate I.

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II.

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III.

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IY.

V.

VI.VII.

Illustrating the measurement of the moon’sdistance ... ... ... To facep.

Determining moon’s distance by observations

at Greenwich and Capetown .

The moon’s orbit round the sun (showing

eccentricity, &c.) .

Illustrating Kepler’s laws

„ moon’s motions.

Showing the forces which perturb the moonIllustrating the action of normal perturbingforces ... .

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VIII.

IX.

X.

XI.

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of nodes

„ tangential „

motion of the perigee„ ,, node

advance of perigee and recession

9

20

27

59

77

81

99

107

115

131

134

* These small photographs are not given in the subscribers’ copies.