Errata

North Star, from the Pole the distance of the Sights being made Radius, let the Stile be rivetted to the end of a straight Ruler; then when you would make use of it, lay the Ruler on an Horizontal Plane, so that the end to which the Stile is fixed may over hang, then look through the Eye-sight, moving the Instrument till you see the North Star appears to touch the circumference of the hole in the other Sight, on the same hand with the Girdle of Cassiopea, or on the opposite side to that whereon the Star in the Great Bears Rump is, at that time then draw a line by the edge of the Ruler, and it will be a true Meridian line, as is very easy to demonstrate. I do not hear that any of the Occultations of Aldebaran by the Moon were observed last year. I expected several, but was always hindered by the weather from observing any. I hope to have better success this year, before the Moons visible way leaves that Star. A Note on this Letter by the Publisher. It is very likely that the Black Wood mentioned in this Letter is Oak, which has lain so long as to be turn'd of that colour by the Vitriolick juices of the earth in which it has lain, as galls, and a solution of Vitriol turn of that colour. I never saw any Oak that had lain any time in any kind of earth, where water came to soak into it, that was not turned of that colour: and I have seen many Trees of Black Wood of great bigness, taken up (as well as lesser pieces) and all of it was Oak. It looks at first taking up like Ebony, is very ponderous, but as it dries, it splits, grows friable, light, and comes to be good for little. ERRATA in No. 267. P. Ag. 715. l.33. lege definire: pag. 710. l. 13. pro Corpusculis, lege quasi corpusculis. Printed for Sam. Smith & Benj. Walford, Printers to the Royal Society, at the Princes Arms in St Pauls Church-yard. 1701.