Or, an Introduction to Useful Knowledge, Being a Compilation of Real Experiments and Improvements, in Several Pleasing Branches of Science, ON The Following Subjects, Viz. Mechanics, Electricity, Optics, Construction of Optical Instruments, &c. Grinding and Polishing Optic Glasses. Clock and Watch-making and Astronomy. The Miscellaneous Articles Contain the Most Approved Art of Drawing, Etching, Engraving, Crayon Painting, Gilding on Glass, Pots, &c. Silvering Looking Glasses, &c. Lackering, Varnishing, Soldering, Casting in Plaster &c. Cements, Glues, Staining Wood, and A Composition for Ornaments, &c. &c. &c. By John Imison