Horologia Nova : Or, The new art of dialling in theory and practice. In which is demonstrated, that all the variety in this science consists in the construction of three dials only. Also, the rationale and use of the lines of latitudes and hours, on the dialling-sector and trigon, with all requisite calculations. The whole illustrated in a large copper-plate. By B. Martin. - Martin, Benjamin, (Printed for, and sold by the author, in Fleet-Street, No. 171. and by the booksellers in town and country,, 1770)