Part 12

_l._ _s._ _d._ Variety of pocket cases of Drawing Instruments, } in Silver, from 3l. 3s. to 20 0 0 Ditto, in Brass, from 5s. to 5 5 0 Magazine Cases, in Silver, from 12l. to 150 0 0 Ditto, in Brass, from 5l. to 50 0 0 Circular Compasses to describe a Circle as small } as a pin’s head, from 3s. to } 0 7 6 Long Hand Drawing-pens, from 1s. to 0 5 0 Compasses in Brass, with shifting points, as the } Ink and Black Lead points, from 2s. 6d. to } 1 1 0 Plain Compasses, from 6d. to 0 5 0 Beam Compasses, for drawing large circles, from 12. to 3 0 0 Proportionable Compasses, from 1l. 1s. to 5 5 0 Triangular Compasses, from 14s. to 0 18 0 Elliptical Compasses, for Ovals, from 1l. 11s. 6d. to 5 5 0 Hair Compasses 0 7 6 Bows for drawing curved lines, from 4s. to 0 10 6 Sets of Feather-edge Scales, in Brass, Ivory, or } Wood, from 12s. to } 1 16 0 Plain ditto, or Plotting ditto, in ditto, from 8d. to 0 18 0 Gunter’s 2 feet, and 1 foot Scales, in Brass or } Wood, from 2s. to } 2 2 0 Protractors of all sorts, from 1s. 6d. to 1 16 0 Parallel Rules, from 6 to 36 inches, from 2s. 6d. to 1 16 0 Cross-bar ditto, in Brass, Ivory, or Wood, } from 4½ } inches, to 3 feet, from 10s. 6d. to } 3 0 0 Sectors, in ditto, from 2s. 6d. to 4 14 6 Theodolites, from 3l. 3s. to 6 6 0 Ditto, with Vertical arch, Spirit Levels, } Telescope, _&c._ from 10l. 10s. to } 21 0 0 Plain Tables, from 3l. 3s. to 5 5 0 Circumferentors, the principal Instrument for } Surveying in the West-Indies, from 1l. 16s. to } 3 13 6 Gunter’s four pole chains, from 6s. to 0 12 0 Spirit Levels of all sorts, from 5s. to 12 12 0 Pentographia, for the ready and exact } reduction or copying of Schemes, } Drawings, Prints, _&c._ } 4 14 6 Measuring Wheels for Surveying, } from 4l. 14s. 6d. to } 6 6 0 Hadley’s Quadrants, with Diagonal Divisions 1 14 0 Ditto, with a Nonius, from 2l. 2s. to 3 13 6 Ditto, all in Brass, from 3l. 13s. 6d. to 6 6 0 Davies’s Quadrant, from 12s. to 1 1 0 Cole’s ditto, from 18s. to 1 5 0 Sutton’s ditto 0 6 0 Gunter’s ditto, from 3s. 6d. to 1 1 0 Horizontal Sun Dials, for all Latitudes, } from 5s. to } 10 0 0 Ring Dials, from 10s. 6d. to 21 0 0 Azimuth Compasses, from 5l. 5s. to 10 0 0 Amplitude ditto, from 1l. 7s. to 5 5 0 Mariner’s Compasses, either for the Cabin, } or Binacle, from 7s. 6d. to } 3 13 0 Pocket Compasses, from 1s. to 1 11 6 Large Orreries, from 50l. to 250 0 0 Armillary Spheres, from 12l. to 50 0 0 Seventeen inch Globes 6 6 0 Fifteen inch ditto 5 5 0 Twelve inch ditto 3 3 0 Nine inch ditto 2 2 0 Six inch ditto 1 16 0 Three inch ditto, in a case, from 8s. to 0 10 0 Large double Barrell’d standing air pumps 25 0 0 Apparatus to ditto, from 3l. 3s. to 12 12 0 Double Barrell’d table air pumps, } with their apparatus, from 5l. 15s. 6d. to } 20 0 0 Single Barrell’d ditto 2 12 6 Apparatus to ditto 2 2 0 Electrical Machines, in Brass, with apparatus, } box, _&c._ from 5l. 5s. to } 13 13 0 Barometers, from 1l. 1s. to 1 16 0 Ditto & Thermometer, in one frame, from 1. 11s. 6d. to 2 12 6 Barometer, Thermometer, and Hydrometer, all in } one frame, from 2l 12s. 6d. to } 3 13 6 Farenheit’s Thermometers, in mahogany cases, } from 1l. 5s. to } 1 11 6 Pocket ditto, in black cases, from 12s. to 1 1 0 Spirit Thermometers, on box scales, for hot-houses 0 10 6 Hydrometers, in Ivory, from 4s. to 0 5 6 Ditto, in copper, with weights, _&c._ for } proving Spirits, from 1l. 1s. to } 1 5 0 Hydrostatic Balance, with apparatus, _&c._ 1 15 0 Speaking Trumpets, from 10s. to 1 11 6 Hearing ditto, from 7s. 6d. to 1 1 0 Reflecting Telescopes, from 1l. 16s. to 50 0 0 Refracting ditto, of various lengths, with four or } six glasses, from 7s. 6d. to } 6 6 0 Double reflecting Microscopes, from 3l. 13s. 6d. to 7 7 0 Solar ditto, in Brass, from 4l. 4s. to 6 6 0 Wilson’s pocket ditto, from 1l. 5s. to 2 12 6 Opake ditto, from 2l. 12s. 6d. to 3 13 6 Cloth ditto, from 3s. 6d. to 0 7 6 Flower ditto, from 3s. 6d. to 0 5 0 Diagonal Machines for viewing prints, from 16s. to 1 11 6 Large Book Camera Obscura, from 4l. 4s. to 5 5 0 Box Camera Obscura, from 10s. 6d. to 2 2 0 Scioptric Ball and Socket, in Wood 0 7 6 Opera Glasses, from 5s. to 2 12 6 Prospect ditto, from 8d. to 0 10 6 Magic Lanthorn, without objects, from 1l. 1s. to 1 7 0 Magic Lanthorn sliders, with objects, from 5s. to 0 10 6 Mirrors, convex or concave, of all sizes, in black } frames, from 10s. 6d. to } 16 16 0 Prisms, from 6s. to 1 1 0 Reading Glasses set in a variety of curious } frames, from 2s. 6d. to } 2 12 6 Watchmaker’s Glasses, in frames, from 1s. to 0 10 6 Concave ditto, for short sighted persons, } from 1s.6d. to } 2 2 0 Spectacles ground on brass tools, and set in } silver, tortoise shell, horn, } _&c._ from 1s. to } 1 7 0 Achromatic, Opera, and Prospect glasses, } from 1l. 1s. to } 1 16 0

Achromatic Telescopes of any length, at 1l. 1s. each foot. Gauging Rules, Carpenter’s Rules, and all other kind of Rules, at the usual Prices.

The Eleventh Edition of HARRIS on the Globes, with the Description and Use of the Orrery, 3s. 6d. The Use of the Sector and plain Scale explained, 1s. The Use of HADLEY’s Quadrant explained, 6d. A fine Print of the Orrery, on imperial paper, 2s. A smaller ditto, 6d.

Variety of other Instruments too tedious to mention, are made and sold at the above place: Where any Gentleman, by Letter, or other Directions, may depend on being as faithfully served as if present. And as I have been long in the Wholesale part of the Business, Merchants, _&c._ may be sure of being supplied on the Best Terms. As also by M. ALLISON, at _Falmouth_.

FOOTNOTES:

[1] By the Orbit of a Planet is commonly understood the Tract or Ring, described by its Center round the Sun, but by the Plane of the Orbit is meant a flat Surface extended every way thro’ the Orbit infinitely.

[2] N. B. According to _Biachini_’s Observations, _Venus_’s axis inclines 75 degrees from the perpendicular to the plane of the Ecliptic (which is 51½ deg. more than the axis of our Earth) her Tropics are only 15 deg. from her Poles, and her Polar Circles at the same distance from her _Equator_; so that the Sun’s greatest Declination on each side of her _Equator_ is 75 deg. by which she must undergo a much greater variety of seasons than we do on our Earth.

[3] ☌ Is a mark commonly used for conjunction; thus ☌ with the ☉, is to be read conjunction with the Sun.

[4] _Prob. VI._

[5] _Prob._ XIII.

[6] The insensible change in the Longitude, Right Ascension, and Declination of the Fixed Stars, made by their slow motion, parallel to the ecliptic (being but 1 degree in 72 years) is not worth notice in this place.

[7] _Phases_ of the Moon are those different appearances we observe in her, according to her position in respect to the Sun and Earth.