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 Hygroscopes are Instruments, to discover the degrees of Moisture and Drought of the Air. 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
confirm the indication. And more lately, in very dark daies, I had the same confidence upon the same ground, and I was not disappointed.
3. Again, if the Mercury ascends to a good height after the fall of rain (as sometimes, but less often it does) then I look for a setled serenity; but if it proceeds after rain in a descending motion, then I expect a continuance of broken and showry weather. But in all, as I only say, For the most part, so I dare not positively declare it an affirmative result, but do refer it to the remarks of others. And this may explicate the Notes 6. and 14 of Num. 9. into more clearness.
4. That we find the Weather and our Bodies more chill, cold, and drooping, when the Mercury is lowest, and the Air lightest, besides other causes, I guess, That as Air is to us the breath of life, as water is to Fishes; so, when we are deprived of the usual measure of this our food, 'tis the same to us, as when the water is drawn ebb from Fishes. But I would much rather be instructed by others, then offer much in this kind.
5. The lowest descent of the Mercury in all the time, since I have observed it, was Octob. 26. 1665. in the Evening, when it was very near at 27½ Inches. Which I find thus circumstanced with the weather in my notes.
Oct. 25. Morning; Mercury at 28½ Inch. Great storms and much rain.
Oct. 26. Morning; Merc. at 28. winds quiet, thick dark clouds.
Oct. 26. Evening; Merc. at 27½. That day, and some daies following, the weather was variable, frequent rain, and as you see, the Mercury lower, than usual.
6. Over the place, where this Mercurial Cane stands, I have set a Wind vane, with purpose of exactness, of a Streamer in Brass so large, and pointing to a Board indented in the Margin, that I can at a sure Level upon the Vane, take every of the 32. points of the Wind, half points, and quarter points, at good distance. Otherwise we may find our guesses much deceived, as the best guessers, upon trial, do acknowledge. And this exactness may become the Wheel-ballance, which shews the minutest variations almost beyond imagination. And thus any servant, at the approach of a thick Cloud, or other Meteor, higher or lower, or at the rising of a storm or fresh wind in the night, or day, may bring a report of the Weight of the Air, as certainly and almost as
easily, as of the Sun from the Dial in a Sunshine. It were good to have an Index of Winds, that discover'd as well their Ascent and Descent, as their Side-coastings.