probably that contained in an interesting volume, which may be seen in
the library of the R. A. S., entitled _Chinese Researches_, by
Alexander Wyllie (Shanghai, 1897).

[4] Sir George Airy was very jealous of this honourable title. He
rightly held that there is only one Astronomer Royal at a time, as
there is only one Mikado, one Dalai Lama. He said that His Majesty's
Astronomer at the Cape of Good Hope, His Majesty's Astronomer for
Scotland, and His Majesty's Astronomer for Ireland are not called
Astronomers Royal.

[5] _Annals of the Cape Observatory_, vol. x., part 3.

[6] The parallax of the sun is the angle subtended by the earth's
radius at the sun's distance.

[7] A. R. Hinks, R.A.S.; _Monthly Notices_, June, 1909.



11. HISTORY OF THE TELESCOPE


Accounts of wonderful optical experiments by Roger Bacon (who died in
1292), and in the sixteenth century by Digges, Baptista Porta, and
Antonio de Dominis (Grant, _Hist. Ph. Ast_.), have led some to
suppose that they invented the telescope. The writer considers that it
is more likely that these notes refer to a kind of _camera
obscura_, in which a lens throws an inverted image of a landscape
on the wall.