¶. 6. Of Italick, and other Standing Gages.
These Gages are to measure (as aforesaid) the Slope of the Italick Stems, by applying the Top and Bottom of the Gage to the Top and Bottom Lines of the Letters, and the other Side of the Gage to the Stem: for when the Letter complies with these three sides of the Gage that Letter hath its true Slope.
The manner of making these Gages (and indeed all other Angular Gages) is thus.
Place one Point of a Pair of Steel Dividers upon the thin Plate aforesaid, at the Point c or d (in Fig. D in Plate 10.) and with the other Point describe a small fine Arch of a Circle; as, e f or g h. In this Arch of the Circle must be set off on the Gage a 110 Degrees, and on the Gage b 70 Degrees, and draw from the Centres c and d two straight Lines through those numbers of Degrees: Then Filing away the Plate between the two Lines, the Gages are finished.
To find the Measure of this, or any other number of Degrees, do thus; Describe a Circle on a piece of Plate-Brass of any Radius (but the larger the better) draw a straight Line exactly through the Centre of this Circle, and another straight Line to cut this straight Line at right Angles in the Centre, through the Circle; so shall the Circle be divided into four Quadrants: Then fix one Foot of your Compasses (being yet unstirr’d) in one of the Points where any of the straight Lines cuts the Circle, and extend the moving Foot of your Compasses where it will fall in the Circle, and make there a Mark, which is 60 Degrees from the fixed Foot of the Compasses: Then fix again one Foot of your Compasses in the Intersection of the straight Line and Circle that is next the Mark that was made before, and extend the moving Foot in the same Quadrant towards the straight Line where you first pitch’d the Foot of your Compasses, and with the moving Foot make another Mark in the Circle. These two Marks divide the Quadrant into three equal Parts: The same way you may divide the other three Quadrants; so shall the whole Circle be divided into twelve equal Parts; and each of these twelve equal parts contain an Arch of thirty Degrees: Then with your Dividers divide each of these 30 Degrees into three equal Parts, and each of these three equal Parts into two equal Parts, and each of these two equal Parts into five equal Parts, so shall the Circle be divided into 360 equal Parts, for your use.
To use it, describe on the Centre of the Circle an Arch of almost a Semi-Circle: This Arch must be exactly of the same Radius with that I prescribed to be made on the Gages a b, from e to f and from g to h; then count in your Circle of Degrees from any Diametral Line 110 Degrees; and laying a straight Ruler on the Centre, and on the 110 Degrees aforesaid, make a small Mark through the small Arch; and placing one Foot of your Compasses at the Intersection of the small Arch, with the Diametral Line, open the other Foot to the Mark made on the small Arch for 110 Degrees, and transfer that Distance to the small Arch made on the Gage: Then through the Marks that the two Points of your Compasses make in the small Arch on the Gage, draw two straight Lines from the Centre c: and the Brass between those two straight Lines being filed away, that Gage is made. In like manner you may set off any other number of Degrees, for the making of any other Gage.
In like manner, you may measure any Angle in the Drafts of Letters, by describing a small Arch on the Angular Point, and an Arch of the same Radius on the Centre of your divided Circle: For then, placing one Foot of your Compasses at the Intersection of the small Arch with either of the straight Lines proceeding from the Angle in the Draft, and extending the other Foot to the Intersection of the small Arch, with the other straight Line that proceeds from the Angle, you have between the Feet of your Compasses, the Width of the Angle; and by placing one Foot of your Compasses at the Intersection of any of the straight Lines that proceed from the Centre of the divided Circle, and the small Arch you made on it, and making a Mark where the other Foot of your Compasses falls in the said small Arch, you may, by a straight Ruler laid on the Centre of the divided Circle, and the Mark on the small Arch, see in the Limb of the Circle the number of Degrees contained between the Diametral, or straight Line and the Mark.
If you have already a dividing-Plate of 360 Degrees, of a larger Radius than the Arch on your Gage, you may save your self the labour of dividing a Circle (as aforesaid,) and work by your dividing-Plate as you were directed to do with the Circle that I shewed you to divide.
In these Documents I have exposed my self to a double Censure; First, of Geometricians: Secondly, of Letter-Cutters. Geometricians will censure me for writing anew that which almost every young Beginner knows: And Letter-Cutters will censure me for proposing a Rule for that which they dare pretend they can do without Rule.
To the Geometricians I cross the Cudgels: yet I writ this not to them; and I doubt I have written superfluously to Letter-Cutters, because I think few of them either will or care to take pains to understand these small Rudiments of Geometry. If they do, and be ingenious, they will thank me for discovering this Help in their own Way, which few of them know. For by this Rule they will not only make Letters truer, but also quicker, and with less care; because they shall never need to stamp their Counter-Punch in Lead, to see how it pleases them; which they do many times, before they like their Counter-Punch, (be it of A A V v W w V W, and several other Letters) and at last finish their Counter-Punch but with a good Opinion they have that it may do well, though they frequently see it does not in many Angular Letters on different Bodies Cut by the same Hand. And were Letter-Cutting brought to so common Practice as Joynery, Cabinet-making, or Mathematical Instrument-making, every young Beginner should then be taught by Rules, as they of these Trades are; because Letter-Cutting depends as much upon Rule and Compass as any other Trade does.