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_. [Illustration] 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. End of the Project Gutenberg EBook of The Description and Use of the Globes and the Orrery, by Joseph Harris