The English globe being a stabil and immobil one, performing what the ordinary globes do, and much more / invented and described by the Right Honorable, the Earl of Castlemaine ; and now publish't by Joseph Moxon ...

OPERATION X. To find the hour of the Day by the Sun, together with a second way of composing the Globe, and finding the Globe, and finding the Day of the Moneth.

MANY are the wayes to perform this Operation as to the Hour, But now wee'l insist on four only, each of which has some peculiar Propriety belonging to it; for the First gives us the Hour by the help of the Natural Stile; the Second by an Artificial one; the Third without any Stile at all; and the Fourth (together with the said hour) the Contemplation of se∣veral pleasing Operations at a time, and among the rest this of Composing the Globe by the Shade.

I. Having Compos'd your Globe, (and thus wee'l suppose it in each of the following wayes) look among the Hour Circles (which are, as we said, distinguish'd near the Polar Circles, with

little Roman Figures) and the shade of the North-Pole, or A∣xis of the World (which we may justly call the Natural Stile,) will, during the Sun's Northern Latitude, as well as the shade of the South Pole in his Southern, shew you the Hour. And thus you may find it for a while by the Ordinary Globes, in Circu∣lo Horario, when they are once set or Compos'd, which I won∣der none, of those who writ of their Uses take notice of; I say for a while, for it will only serve your Turn there from March to September.

II. Your String hanging by one End on the North Pole, hold it straight by the other, some little distance from the Globe, and moving it on the Noose, till its shade touch, or cover, the Apex of the South-Pole, 'twill show you (among the aforesaid Polar Roman Figures) the true Hour, even to a minute; for the Sha∣dow of the String (which we call an Artificial Stile, because 'tis Independent and Forrein to the Globe) cutting at that In∣stant the Aequator, and Polar Circles, gives you in each place the Degrees of the hours, and consequently the minutes, since the 4th part of a Degree is an exact minute in time.

III. Look where the shade of Extuberancy cut's on the Ae∣quator, and the great Roman Figures, (which are there for that purpose) will give you without a Stile or more adoe the exact hour, on what side soever of the Globe, you stand; for you must remember that the Extuberancy casts on the Aequator two shades, the one still Preceding or going before the Sun, and the other Following him. Now if this shade be dubious, your Finger (as I show'd you before) will help you, it being the constant Remedy on all Occasions of this Nature.

IV. As now you find the Hour by your String hanging on the Pole, so this Fourth way is to show it you, in case it had hung on the Zenith; nor have you more to do than to hold it by the end as before, and to move it on its Noose 'till its shade concurrs and agrees with that of the Pin in the Zenith, or for more Assurance till the Strings shade fall's so on the upper part of the Pillar or Fulcrum that it would cover the very Nadir, were it not hid, and then where the said String it self, or its shade cuts the Parallel of the Day, there will be the true hour, according to the Roman Figures of the Polar Circles.

This way I would have you well observe for from hence I shall hereafter lead you to the Contemplation (as I hinted before) of several pleasing and useful Operations at one glance or view; and to give you a little Taste at present, I will here shew you the Second way of Composing the Globe by the shade.

Having for Expedition's sake, turned the North-pole of the Globe, as near as you can guess to that of the World, Hold up your String with one hand to the Sun in the manner now pre∣scribed; That is to say, 'till the String hanging from the Ze∣nith) casts its shade on the Nadir, then move the Globe with your other hand, and making by a proportionable motion of the String its shade to pass still throu' the said two points, observe when it cuts the Parallel of the day at the like hour with that, which the shade of the illuminated Pole indicates, and your Globe will be composed; or, to express this in fewer words, Move thus the Globe, till the shade of the string and the shade of the illumi∣nated Pole agree in the Hour. Nay fixing your String in the Zenith as before, and fastning a Thred on the North-pole, do but hold up both to the Sun till the shade of the String passes the Nadir, and that of the Thred the South Pole, if any body then moves your Globe about till the two shades (passing still throu' the foresaid Points) intersect on the Parallel of the Day, you have your intent; for the Sun being you see in the Planes of the Thred and String▪ he must be in their Intersection. i. e. in the Parallel of the Day; but 'tis impossible for him (as we show'd you) to be in the plane of that Parallel, on the true side of the Meridian, except the Globe be Compos'd, for the corresponding Circles of the Globe and Heavens can never else agree; there∣fore the Operation is true; and if so, let the Globe be but on a Meridian Line, or any way else Compos'd, and the Agreement of the hour in both places, or the Intersection of these two shades shews the Sun's Parallel and consequently the Day of the moneth.

So much then for this second way of composing the Globe, and finding the Day of the Month, which first came into my thoughts by reflecting on the Projection of that great man Mr. Oughtred, who would have bin the Wonder of this Age, had he bin as ambitious and forward, as he was throughly learned.

Notes

• Op. 3. pag. 8.
• The 1st. way.
• The 2. way.
• The 3d. way.
• 2. pag. 6.
• The 4th. way.
• A Memoran∣dum.
• vid. the particulars in the conclusion or last Chap∣ter. The 2d. way of composing the Globe by the shade.
• Demonstrati∣on.
• Op. 3. pag. 8
• The 3d. way of finding the day of the month.