VI. AN APPENDIX to the GEOMETRICAL AND GRAPHICAL ESSAYS, containing the following Table by Mr. JOHN GALE, viz. a Table of the Northings, Southings, Eastings, and Westings to every Degree and fifteenth Minute of the Quadrant, Radius from 1 to 100, with all the intermediate Numbers, computed to the three Places of Decimals. Price 2s. _In the Press, and speedily will be Published_, LECTURES ON NATURAL AND EXPERIMENTAL PHILOSOPHY, In Five Volumes 8vo. The Second Edition, with upwards of Forty large Plates, considerable Alterations and Improvements; containing more complete Explanations of the Instruments, Machines, &c. and the Description of many others not inserted in the former Edition. BY W. JONES, MATHEMATICAL AND PHILOSOPHICAL INSTRUMENT MAKER. _ADVERTISEMENT._ _The editor esteems it his indispensable duty, to point out the several improvements which have been made in this work, in order to render it still more acceptable to the public._ _The whole has been carefully revised--many typographical errors corrected--numerous additions and emendations from the author’s own copy incorporated, and some superfluities rejected. Wherever any ambiguity occurred, the editor has endeavoured to elucidate the passage, observing due caution not to misconceive the idea which the author meant to inculcate. A more regular arrangement has been attempted, and occasional notes subjoined: in these, and in other parts of the work, it has been the editor’s primary object to ascertain facts, not to decide peremptorily. Should he in any instance have erred, he can assure the candid critic, that he shall experience a most sensible pleasure in conviction._ _The principal additions are_, Accounts of the latest improvements which have been made in the construction of microscopes, particularly the lucernal. A description of the glass, pearl, &c. micrometers, as made by Mr. Coventry, and others. An arrangement and description of minute and rare shells. A descriptive list of a variety of vegetable seeds. Instructions for collecting and preserving insects, together with directions for forming a cabinet. A copious list of objects for the microscope. A list of Mr. Custance’s fine vegetable cuttings. _With respect to the plates, three new engravings are introduced, viz._ PLATE IV. Exhibiting the most improved compound microscopes, with their apparatus. PLATE XIV. Microscopical figures of minute and rare shells. PLATE XV. Microscopical figures of a variety of vegetable seeds. _Many additional figures have been inserted in other plates, and a number of errors in the references corrected._ _A complete list of the plates and a more extensive index are also added._