It is difficult to understand how so striking a natural phenomenon should have failed to attract the attention of physicists and astronomers until the middle of the seventeenth century, or how it could have escaped the observation of the Atabian natural philosophers in ancient Bactria, on the euphrates, and in the south of Spain. Almost equal surprise is excited by the tardiness of observation of the nebulous spots in Andromeda and Orion, first described by Simon Marius and Huygens. The earliest explicit descriptions of the zodiacal light occurs in Childrey's 'Britannia Baconica',* in the year 1661. p 139 [footnote] *"There is another thing which I recommend to the observation of mathematical men, which is that in February, and for a little before and a little after that month (as I have observed several years together), about six in the evening, when the twilight hath almost deserted the horizon, you shall see a plainly discernible way of the twilight striking up toward the Pleiades, and seeming almost to touch them. It is so observed any clear night, but it is best illac nocte. There is no such way to be observed at any other time of the year (that I can perceive), nor any other way at that time to be perceived darting up elsewhere; and I believe it hath been, and will be constantly visible at that time of the year; but what the cause of it in nature should be, I can not yet imagine, but leave it to future inquiry." (Childrey, 'Britannia Baconica', 1661, p. 183.) This is the first view and a simple description of the phenomenon. (Cassini, 'Découverte de la Lumi dfd éleste qui paroît dans le Zodiaque', in the 'Mém. de l'Acad.', t. viii., 1730, p 276. Mairan, 'TraitéPhys de l'Aurore Boréale', 1754, 0. 16.) In this remarkable work by Childrey there are to be found (p. 91) very clear accounts of the epochs of maxima and minima diurnal and annual temperatures, and of the retardation of the extremes of the effects in meteorological processes. It is, however, to be regretted that our Baconian-philosophy-loving author, who was Lord Henry Somerset's chaplain, fell into the same error as Bernardin de St. Pierre, and regarded the Earth as elongated at the poles (see p. 148). At the first he believes that the Earth was spherical, but supposes that the uninterrupted and increasing addition of layers of ice at both poles has changed its figure; and that as the ice is formed from water, the quantity of that liquid is every where diminishing.