Clavis horologiæ; or, A key to the whole art of arithmetical dyalling [electronic resource] : in two parts. The first shewing how to draw the hour-lines on all manner of regular dyals, and how to reduce all irregular dyals into regular forms by means of an new latitude and new declination, and that arithmetically. The second part sheweth how to place all manner of furniture on all sorts of dyals, let them be never so irregular, and that arithmetically; whereunto is annexed the tables of the altitude of the sun for every hour of the day at his entrance into the 12 signs from one degree of latitude to 90; with tables of azimuth to each latitude, and for every hour of the day at his entrance into each sign, with many other tables useful in the art of shadows. Whereunto is annexed an appendix, being the explication of the pyramidical dyal set up in his Majesties garden at White-Hall, 1669. In which very many sorts of dyals are contained; by which, besides the hours of all kinds diversly expresed, many things relating to geography, astrology and astrononmy, are by the suns shadow ma.