Virrationality. The character of a surd root, and shews, according to the index of the power that is set over it, or after it, that the square, cube, or other root, is extracted, or to be extracted; thus, √16, or √2 16, or √ (2) 16, is the square root of 16.25, the cube root of 25, &c.

- the differences, or excess.

Q or q, a square.

C or e, a cube.

Q Q, The ratio of a square number to a square

number.

These and several other signs and symbols, we meet with in mathematical and algebraical works; though authors do not confine themselves to them, but express their knowledge different ways, yet so as to be understood by those skilled in the science. In algebraical works, therefore, in particular, gentlemen should be very exact in their copy, and compositors as careful in following it, that no alterations may ensue after it is composed: since changing and altering work of this nature is more troublesome to a compositor than can be imagined by one that has not a tolerable knowledge of printing. Hence it is that very few compositors are fond of algebra, and rather choose to be employed upon plain work, though less profitable to them than the former; because it is disagreeable, and injures the habit of an expeditious compositor besides. In the mean time we venture to say, that the composing of algebra might be made more agreeable were proper cases contrived for the letter and sorts belonging to such work, where it is likely to make a return towards its extraordinary charges.

Seven of the Planets sometimes imply the seven days of the week.

Dies Solis, Sunday

Dies Luna, Monday

Dies Martis, Teusday

Dies Saturni, Saturday

The Dragon's Head, or ascending node, and The Dragon's Tail, or descending node, are the two points in which the eclipses happen. The Aspects.

Conjunctio; happens when two planets stand under each other in the same sign and degree.

Oppositio; happens when two planets stand diametrically opposite each other.

A Trigonus; happens when one planet stands from another four signs, or 120 degrees; which make one third part of the ecliptic.

☐ Quadril; happens when two planets stand three signs from each other, which make 90 degrees, or the fourth part of the ecliptic.

Sextil; is the sixth part of the ecliptic, which is two signs, and make 60 degrees.

New Moon.

First quarter of the Moon.

Full Moon.

(Last quarter.

Many are the signs and symbols which astronomers have invented to impose upon the credulity of the vulgar, who are the chief supporters of almanacks; and especially of such as abound in predictions of any kind: among which we reckon those signs which give notice, on what day it is proper to let blood; to bathe and to cup; to sow and to plant ; to take physic; to have one's hair cut; to cut one's nails; to wean children; and many other alike nonsensical observations, to which the lower class of people are particularly bigotted; besides giving credit to the marks that serve to indicate hail, thunder, lightning, or any occult phænomena.

PHYSICAL SIGNS AND ABBREVIATIONS.

R Stands for Recipe, or Take.

ā, aa, of each a like quantity.

j stands for one; ij for 2; and so on.
signifies semi, or half.

gr. denotes a grain.

One pound makes 12 ounces.

One ounce contains 8 drachms.

One drachm is equal to 3 scruples.

One scruple consists of 20 grains.

One grain has the weight of a barley-corn,

P. stands for particula, a little part, and means so much as can be taken betwixt the ends of two fingers.

P. aq. stands for, partes æquales, or equal parts. q. s quantum sufficit, or as much as is sufficient. q. p. quantum placit, or as much as you please. s. a. secundem artem, or according to art.

MUSICAL CHARACTERS.

TUNE and Time are the two chief characteristics of musical notes. In time, the distinction, measure, and proportion of notes and rests are to be observed.

As to distinction, they have different characters; and different names with relation to time.

The rests or pauses are of the same length or quantity with the notes that stand above them: as follow

&

Treble, or G Clef; the line passing through

the middle of the curve is called G, and the other letters are calculated therefrom. This Clef is usually placed upon the second line, though it sometimes appears upon the lowest.

Tenor, or C Clef; the line passing through the body is called C; it is commonly placed upon the lowest, the second, the middle, or the fourth line.

Base, or F Clef; the line passing between the
points is called F; it is generally set upon
the fourth line, but sometimes it occurs
upon the middle one.

Slow Time, or Binary Measure; it is counted
by beating twice up and twice down in each
bar. A bar most commonly contains four
crotchets, or their value.
Moderate quick Time, or the Second Mood;
it is counted either by four quick beats,
or two moderate in a bar This character
reversed signifies the quickest time, which
is counted by two beats in a bar.

Semibreve; this is the longest note in modern music, and is equal to two Minims, in the time of playing or singing.

Minim; equal to two Crotchets.

Crotchet; equal to two Quavers.

Quaver; equal to two Semiquavers.

Semiquaver; equal to two Demisemiquavers.

Demisemiquaver; thirty-two of which are equal to one Semibreve. This is the shortest note in modern music.

Rests.

To each of the Notes there belongs a corresponding mark of silence, called a Rest; which signifies that silence is to be kept, so long as that note which it represents would require to be sung or played. The rests are here shewn by themselves, but in the next page they are connected with their respective names and notes.

ww Direct. :S: Repeat. Natural.

bt Flat.

**Sharp.

Slurs.