in the Twilight, and fome diminution of the Cold, and a small Heat at Mid-day.

ON the twenty fourth of January the Air was alfo clear; and then they firft faw the Limb of the Sun in the South; and afterwards the whole Sun above the Horizon.

ON the fecond of May a ftrong Wind removed the Ice from certain Places; in the Sea, they had a fmall Heat fome Days, but mostly cold Winds, Snow, and Showers.

IT is remarkable in these Obfervations, that the Sun left them the fecond of November, which by Refraction (that makes it appear nineteen Days fooner) fhould not have been fo foon. It feems the Difference in the Atmosphere may cause fomething of this; for the Sun coming to the Horizon after three Months abfence, the Air was there thicker and groffer than it was in the former Year; when the Sun had been long under the Horizon. Yet I doubt whether the Diversity of the Air can caufe it to disappear fo many Days fooner; and it was otherwife obferved by thofe in 1634, when they wintered at Spitzberg: for the Sun did then leave them the ninth of October, and after a long abfence appeared again the thirteenth of February 1634; and thefe two Days are almoft equidiftant from the eleventh of December. And in the laft of the two Obfervations, they might easily err a few Days; for being in their Bed they did not obferve the Sun rife on the tenth, eleventh, and twelfth of February: or fome Clouds or Rain might hinder their feeing it.

CHAP.

CHA P. XXVII.

Of the Shadows which upright Bodies caft when enlightned by the Sun; and of the Divifions of the Earth that arife therefrom.

S

EEING Bodies in different Places of the

Earth caft Shadows which are directed to different Points; and that other Varieties are observed therein; Men have admired hereat, as not knowing the Caufe. And the Inhabitants of the Earth are thereby divided into three Sorts; which Divifion is alfo applied to the Parts of the Earth's Superficies they inhabit; whence fome are called Amphifci, others Heterofcii, and the reft Periscii; which we fhall explain a little, tho' it belongs not directly to Geography.

SHADOW S take their Denominations from the Points they are ftretched out to, as the Oriental Shadows, or Occidental, from the Sun's being West or Eaft; but we are to confider thofe chiefly that are in the Plain of the Meridian, from upright Bodies, the Sun being in the Meridian: and thefe are either North or South.

THE Heterofcii are thofe that have the Shadow of upright Bodies tending to the North or South, every Day of the Year.

PERISCII are those that have fuch Shadows going round to all Points in one Day.

AMPHISCII

AMPHISCII are those that have fuch Shadows tending to the North fome Days; and in other Days to the South. But not to exclude Places in the Tropics, for this laft kind we fubftitute the Afcii, who on a certain Day of the Year have no Meridian Shadow; and thefe are either 1. Amphifcii, that have no Meridian Shadow on two Days of the Year; or on fome Days that Shadow tends to the North, and on other Days to the South: or, 2. They are Heterofcii, who on one Day have no Meridian Shadow; and on the other Days the Shadow is always ftretched to North or South.

PROPOSITION I.

The Shadow of upright Bodies tends to a Point oppofite to that in which the Sun is.

THOSE that are skilled in Optics and Dialling tell us, that the Shadow, the dark Body, and the luminous Body are all in one Plain; and the end of the dark Body of the Shadow, and the luminous Body are in one Line; for the erect Body and it's Shadow with a Line from their two Extremities, conftitute a Triangle, the three Sides of which must be in one Plane; and the Body being upright, the Plane thro' it must be fo alfo; and thus in a vertical Plane. And because the upright Body is between the Sun and the Shadow, these two must be in oppofite Points.

THERE are three Parts in the Shadow; 1. The dark Part, which is terminated by a Line from the upper Part of the Limb. 2. The central Shadow, intercepted between the Ray from the Center, and that from the upper Limb. And, 3. the Penumbra; between the central Ray, and the Ray from the inferior Limb.

PRO

PROPOSITION II.

Those that live under the Tropics are Afcii-
Heterofcii.

FOR when the Sun is in the Tropic of Cancer, or Capricorn, upright Bodies have no Shadow; but when the Sun goes nearer the Equator, the Shadow is projected to the North or South.

PROPOSITION III.

Thofe that live in the Torrid Zone are Afcii
Amphifcii.

FOR take any Point on the Globe, in that Zone; and the Sun will be twice in the Year in the Zenith of that Place; and fo there will be no Shadow of upright Bodies. But in other Days the Shadow is projected either to the North, if the Sun be to the South of them; or to the South, if that be to the North of them.

PROPOSITION IV.

Thofe in the Temperate Zone are Heterofcii.

FOR the Sun all the Year is ftill more foutherly from those in the North Temperate Zone, and more northerly from those in the South Temperate Zone; whence the Shadow must always tend North to the one, and South to the other.

PRO

PROPOSITION V.

Thofe in the Frigid Zone are Periscii.

FOR the Sun doth not fet to them for fome Days, but revolves above the Horizon; fo that the Shadow muft turn round with it.

PROPOSITION VI.

A Place being given in the Torrid Zone, to find when the Inhabitants there will be Afcii.

FIND when the Sun will be vertical to that Place, and there will be two Days when they will have no Shadow; as in Prop. iii.

PROPOSITION VII.

The Day of the Year being given, to find thofe Places where the People are Afcii, or without Shadows.

FIND the Places that the Sun is vertical to that Day, by Chap. xxiv. Prop. ix. and those are the Places.

PROPOSITION VIII.

A Place being given in the Frigid Zone, to find when the People there are Perifcii.

FIND when the Sun will not fet to them, by Prop. x. Chap. xxiv. and those are the Days.

PRO