But it is to be premised, that the Worthy person, who was alledged as the Author of the Observations, delivered of this kind in the last of these _Tracts_ (Dr. _Beale_) gives notice, That {164} 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: [Sidenote: __Hygroscopes_ are Instruments, to discover the degrees of Moisture and Drought of the Air._] 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 _Calendar_ or _Journal_ taken in taken in _Tangier_, and in some of our _Northern_ and most _Southern_ parts of _America_. I have store of _Hygroscopes_ 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 1665/6, 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 a 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 {165} confirm the indication. And more lately, in very dark daies, I had the same confidence upon the same ground, and I was not disappointed.