[13] I may notice another error sometimes made. It is said that the shadow of a satellite appears elliptical when near the edge of the disc. The shadow is in reality elliptical when thus situated, but appears circular. A moment's consideration will show that this should be so. The part of the disc concealed by a satellite near the limb is also elliptical, but of course appears round.
[14] From a paper by Mr. Breen, in the 'Popular Science Review,' October, 1864.
[15] 'Intellectual Observer' for July, 1867, to which magazine the reader is referred for full details of Mr. Howlett's method of observation, and for illustrations of the appliances he made use of, and of some of his results.
[16] As the sun does not attain such an altitude as 18° during two months in the year, it is well to notice that the true length of the sun's apparent solar diameter is determinable even immediately after sun-rise, if the line of graduation is made to coincide with the horizontal diameter of the picture on the screen—for refraction does not affect the length of this diameter.
[17] The words "Left" and "Right" indicate which end of the sun's ecliptical diameter is uppermost at the dates in upper or lower row respectively.
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