The English academy, or, A brief introduction to the seven liberal arts grammar, arithmetick, geometrie, musick, astronomie, rhetorick & logic : to which is added the necessary arts and mysteries of navigation, dyaling, surveying, mensuration, gauging & fortification, practically laid down in all their material points and particulars, highly approved to be known by the ingenious, and as such are desirous to profit, or render themselves accomplished : chiefly intended for the instruction of young scholars, who are acquainted with no other than their native language, but may also be very useful to other persons that have made some progress in the studies of the said arts / by John Newton.

Horology, or the Curious Art of Dial∣ing made plain and easy in describing, and directing the positions of the Sundry sorts of Dials now in use; also to know by a Sun-dial the time of the night by the Moons shaddow.

DIaling is a very Curious ART, and re∣quires much Care and Industry to come up to it in all Points; for of Dyals there are sundry sorts, varying in somewhat or other, according to their Places, Positions, and the Suns Degrees, some are movable, and may be carryed from place to place, others fixed, and are found to be Regular, or Irregular; the Regular are such as are on a Plain, di∣rectly towards one of the Eminent parts of the world, as full West, or full East, but the Irregular are those that have no direct pointing to any principal quarters of the world, but rather declines them.

Of those called Regular, they have many names to distinguish them; as, The Meri∣dian East, The Meridian West, The Ho••i∣zontal Dial, The Vertical Northward, and the Vertical Southward, The Aequinoctial below, The Aequinoctial above, the Polar below, and the Polar above.

The Horizontal, is when it is equally di∣stant towards the Horizon.

The Vertical, is a Perpendicular erected above the Horizon, tending directly towards the Vertical point, being Parallel to the Primary Vertical Circle, and is duplex, as North Vertical looking to the other which is South Vertical.

The East and West Meridians have par∣ticularly either of them their several ways, being equally distant from the Meridian Circle.

The Aequinoctials mentioned are those of which either have their several ways e∣qually distant from the Aequator, the one above and the other beneath the Horizon.

The Polars have likewise their different ways, the one being beneath, and the other above, they are found as Parallels to the Worlds Axis.

The Irregular are either inclining, or de∣clining; the first of these is equally distant from any Vertical Circle, and from thence is often called Vertical, though declining from the Primary Vertical, properly so na∣med; and is of two sorts, there being one declining from the South to either East or West, and the other from the North to ei∣ther East or West.

That which inclines falls away from the Vertical Point, having its inclination toward the Horizon, as not being equally distant from it.

As for the hours which these several sorts

of Dials, are to parcel out time unto, they are Reckoned as to the days they make di∣vers, according to the distant Latitudes, the Suns ascending or declining, yet all allow 24 hours to the day and night, dividing each hour into 60 minutes, and those into seconds parts, and smaller proportion of time, till it can be discerned only by imagi∣nation. The days are held in two distincti∣ons, the one natural, and the other Artifi∣cial, the Natural day is accounted 12 hours the Artificial as many as the Sun allows ei∣ther the longer or the lesser it shines.

But to be an exact Horologian, observe these methods, be sure to have the exact E∣levation of the Pole, which to find, you are directed in the treatise of Navigation, for by that your determination of the Center of hours must be had also the stile of the Dial's Altitude, and the order of it, and whate∣ver is requisite beside of that nature; you must likewise know the true Meridian line, that so the Dials-Meridian line may have its place directly under the Meridian of the place where it is posited. And he that un∣dertakes this work, must be furnished with such Mathematical and Astronomical In∣struments and Materials, as may give him a due understanding of the proportions of time, as a Rule, Compass, Astronomical Quadrant▪ divided exactly into 90 degrees, with a description of the hour line & points

and to bring this Ingenious work to perfe∣ction, you must be careful the figures of the hours are set at their proper and proporti∣onable distance to answer the moving of the stiles shaddow, and that your stile be well contrived as to its Form and Altitude, and make your observation to fix it exactly; also be very careful in the Application and Dis∣position of the Dial when it is finished.

But to come to what is more curious, be sure the hours be described, and to do it there are granted to be two right lines sect∣ing each other at right Angles cross ways, one of them being the Meridian line, or the 12th hour line, the other is termed the Occult line, by which the first cross ways are cut to the right Angle, and this is generally called the line of hours, because in it the horary points are designed, but if we come to its more proper denomination, it may be called the Aequinoctial line, since it re∣presents the Aequinoctial Circle, the chief rule of all hours.

Thus much being explained as to Dial∣ing, in general, we come now to more par∣ticulars.

If you are desirous to have a right Dial, you must be sure to know its right Center, or the Center of the hour, to do which, be very mindful of the Elevation of the Pole, especially in the Horizontal Dial, or any of that sort, for they will not declare the hours

in any place, but under a certain Elevation, and therefore if they are removed far, you must be again proportioned to that Eleva∣tion Conjecture we then the Pole be Eleva∣ted 49 degrees in this Region, which is 41, place here the foot of your Compass in the Instruments Center, extending the other foot from that to the Aequinoctial line de∣scribed in the instrument, where in that part the 41 degrees is cut by the Radius, so num∣bering from the 12th hour line, and trans∣fer this extension of the Compass upon the Dial, having yet the Compasses foot fixed in the Meridian, and Aequinoctial lines, con∣course, and the other fix in the distant part of the Meridian line, determining, that point to be the hours Center, and so from thence, and each point in the Aequinoctial line, you are to draw all the lines, which some term, the Arches of hours. And fur∣ther a line is to be drawn through the Cen∣ter of the hours, a line Parallel to the Aequi∣noctial, and this is to be accounted the line of the sixth hour, as well in the Evening as the morning, as likewise of the hours of 4 and 5 in the Evening, are to be drawn out beyond the Center of hours, for the like hours in the morning, and so of the rest, e∣qually compeering; and thus you have an exact description of a Horizontal Dial, whose figure you may form as you please, placing the Characters of the hours at the end of the line.

If you design a Vertical Dial, it may be done upon a Regular wall, the same way as the former, yet there is some difference to be observed, not only in the Scituation, but likewise in the Vertical, in case of being cer∣tain of the Center of the hour, the Polar E∣levation degrees are to be here taken for the Altitude of the stile, allowing the degrees complement, though the Horizontal Dial is the contrary; however, there being a distinction between a Vertical to the North, and a Vertical to the South, the Vertical to the North is, as we may suppose, a Meridi∣an Inverted, having the Center of hours downwards falling short, in shewing short, in shewing the hours, for in some Adjacent Countreys, it shews but from 4 to 8 in the morning, and the like in the afternoon, and the South Vertical hath the Center of hours and its stile upwards, shewing from the six in the morning to noon.

A Meridional Dial either East or West, for the first, it must have a Line Pa∣rallel drawn to the Horizon, and a slight Cir∣cle at any opening of the Compass, begin∣ning from the Horizontal line towards the right side where the Eastern Dial is to be drawn, conceiving in the Instrument such an Arch at the like opening of the Compass, in which Arch cut off the Elevation of the Ae∣quator, and carry the Interval to the Circle drawn from the point, and allow the Arch to be cut off.

To frame an Aequinoctial Dial, two lines must be drawn at right Angles, whereof one is to be the Meridian, the other that of the hour, 6 morning and evening, and from the usual section of these lines, draw a Circle as you think fit to be divided into 24 pro∣portionable and equal parts, for in this kind of Dyaling, all the Intervals must be equal as to the hours.

The Polar Dial goes Parallel to the Axis of the world, lying as it were in it, and is to be Elevated above the Horizontal Plain, the same degrees as the worlds pole, the lowermost part in many places, containing not above 4 hours, yet generally the mor∣ning hours are 4 and 5, towards the left side the Evening hours 7 and 8, but the topmost shews the hours from 7 in the mor∣ning to 5 in the Evening, but not the sixth by reason the Sun then is parallel to the Dial glancing then upon its side.

A Dial of Irregular Declination may be best managed by the Marriners Compass, and applying the Semi-Circle divided in the Plan to a competent number of degrees, the pin or stile placed at its Center, so that in that Meridional hour, you will perceive the degree the shaddow cuts, and the way it casts, by the which you may the better determine the species, and how it declines; by which observation, you may draw a Dial in any place, fixing your stile of

what Magnitude you please at right An∣gles.

If you are desirous to find by the shining of the Moon, the hour of the night upon a Dial, suppose you have a Horizontal Sun-Dial, movable or fixed, joyn to it a Dial, by some called a Moon Dial, made up of two Concentrick Circles, where in one you will meet with the day of the Moons Age, by applying a Globule to the number 30, in the other, the 12 hours diversly set down; then knowing the Moons Age, so place your Sun-dial, that the Moon may fairly shine on it, and being placed as for the day, see what hour the Moon shaddows on, as sup∣pose the 8, then place the Globule, the hour you find set down in the Horary Circle, and then again having recourse to the Moons Age, it will give you the hour required, as suppose it be the 12 of the Moons Age, you will find the shaddow about 5 and a half, which is the time, if (as it frequently hap∣pens) the Moon Dial be composed of 3 Cen∣trical Circles, whereof the last and greatest be that of the Moons day, the next to it the hour Circle, and the inmost the Index; let the Index be applyed to the day of the Moon, and then by that Circle, observe what hour, or part of an hour the shad∣dow marks, and you will find the true con∣tent.