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he did not pretend to exactness, but only to excite the carefulness of others in the several distant places, and chiefly such, as can have the assistance of a Wheel-ballance perfectly filled: without both which aids he hopes not to obtain all the benefits and mysteries of this Invention.
This being thus briefly intimated, the Account of the Observations themselves, as they were extracted out of a late Letter of the same Person, are, as followes:
1. As I have fitted and filled the Single Cane, I can say in the general, That I have not yet found any such infallible Prognostick of these changes of weather, which do follow a long serenity, or setled weather. And perchance in brighter Climats it may be constantly infallible. In these Northern Islands, the Clouds are so short, and narrow, and by fickle changes are sometimes emptied upon us, sometimes so neer, as may make so little variation in the weight of the whole Atmosphere of Air, as may sometimes deceive us, or smother and hide from us the causes of fixedness, or of changes. I wish I could see a good Calender or Journal taken in Tangier, and in some of our Northern and most Southern parts of America, I have store of Hygroscopes Hygroscopes are Instruments, to discover the degrees of Moisture and Drought of the Air. of divers kinds, and I do remark them, and the sweatings of Marble, and as many other famed Prognosticks, as I can hear off; but can find nothing so neerly indicative of the change of weather, as this Ballance. Those others are often changed by Dews, which do not at all alter the Ballance, nor alter the state of the weather: And the open Weather-glass is known to signifie nothing at certainty, having a double obedience to two Masters, sometimes to the Weight of the Air, sometimes to Heat, as the service is commanded.
2. And in further confirmation of this Note, I may adde to the former, That in January last 16656, from the fourth, and more especially from the seventh day, for many daies it continued very dark, so that all men expected daily great rain; yet the Mercury held very high, neer to the greatest height; And though in those daies sometimes thick mists arose, and some small rain fell, yet the Quick-silver held at at great height: which did indicate to me, there could then be no great change of weather. As the small rain fell, it yeilded somewhat, not much; and that does more
