cuous which, by putting on a less aperture, may be found to vanish; and therefore, both for the discovery of the fixt Star, and for finding the Satellites of Jupiter, before it be out of the day, or twilight, I alwayes leave the Object-glass as clear without any aperture as I can, and have thereby been able to discover the Satellites a long while before; I was able to discern them, when the smaller apertures were put on; and at other times, to see multitudes of other smaller Stars, which a smaller aperture makes to disappear.
In that notable Asterism also of the Sword of Orion, where the ingenious Monsieur Hugens van Zulichem has discovered only three little Stars in a cluster, I have with a thirty six foot Glass, without any aperture (the breadth of the Glass being about some three inches and a half) discover'd five, and the twinkling of divers others up and down in divers parts of that small milky Cloud.
So that 'tis not unlikely, but that the meliorating of Telescopes will afford as great a variety of new Discoveries in the Heavens, as better Microscopes would among small terrestrial Bodies, and both would give us infinite cause, more and more to admire the omnipotence of the Creator.
Observ. LX.Of the Moon.
HAving a pretty large corner of the Plate for the seven Starrs, void, for the filling it up, I have added one small Specimen of the appearance of the parts of the Moon, by describing a small spot of it, which, though taken notice of, both by the Excellent Hevelius, and called Mons Olympus (though I think somewhat improperly, being rather a vale) and represented by the Figure X, of the 38. Scheme, and also by the Learn'd Ricciolus, who calls it Hipparchus, and describes it by the Figure Y, yet how far short both of them come of the truth, may be somewhat perceiv'd by the draught, which I have here added of it, in the Figure Z, (which I drew by a thirty foot Glass, in October 1664. just before the Moon was half inlightned) but much better by the Reader's diligently observing it himself, at a convenient time, with a Glass of that length, and much better yet with one of threescore foot long; for through these it appears a very spacious Vale, incompassed with a ridge of Hills, not very high in comparison of many other in the Moon, nor yet very steep. The Vale it self A B C D, is much of the figure of a Pear, and from several appearances of it, seems to be some very fruitful place, that is, to have its surface all covered over with some kinds of vegetable substances; for in all positions of the light on it, it seems to give a much fainter reflection then the more barren tops of the incompassing Hills, and those a much fainter then divers other cragged, chalky, or rocky Mountains of the Moon. So that I am not unapt to think, that the Vale may have
