A Discourse concerning the Rising and Falling of the Quicksilver in the Barometer; And What May be Gathered from Its Great Rise in Frosty Weather, as to a Healthy or Sickly Season; Presented the Royal Society March 20. 1683. by the Learned Dr. Martin Lister, Fellow of the R. S.

A discourse concerning the rising and falling of the Quicksilver in the Barometer; and what may be gathered from its great rise in Frosty weather, as to a healthy or sickly season; presented to the Royal Society March 20, 1683, by the Learned Dr. Martin Lister, Fellow of the R.S. Do not offer these things Dogmatically as though I had light upon certain Truths; but only as probable Conjectures, and such as may as well account for the Phenomena of the Barometer, as any I know. I am of opinion, That it is not good, if we intend the Advancement of Natural Philosophy, to let any part of it rest too long upon one Basis; For he that is once well pleased with an Opinion, naturally acquiesces, and seeks no further. However admitting the Gravitation of the Air, I have a mind to try how far I may go in some additional thoughts I have about the Barometer, though they may possibly be much different from what hath hitherto been proposed about it. 1. It is to be observed, that Quicksilver is not affected with the Weather, or very rarely, let that be either Cloudy, Rainy, Windy, or Serene in St. Helena; or the Barbadoes: and therefore probably not within the Tropicks, unless in a violent Storm or Hurricane. The first is affirmed by Mr. Halley, who kept a Glass near two Months in the Island St. Helena, and the other of Barbadoes stands upon the Credit of our Registers. 2. In England in a violent Storm, or when the Quicksilver is at the very lowest, it then visibly breaks and emits small particles, as I have more than once observed; which disorder I look upon as a kind of Fretting; and consequently at all times in its Descent, it is more or less upon the Fret. In this disorder of the Quicksilver, I imagine it hath its its parts contracted and closer put together; which seems probable, for that for Example, the Quicksilver then omits, and squeezes out fresh particles of Air into the Tube, which increasing the Bulk of the Air, and consequently its Elasticity, the Quicksilver is necessarily depressed thereby, that is, by an external force or power; And also the Quicksilver must of itself come closer together in its own internal parts, that is, descend for both reasons. And that much Air is mixt with it, appears from the Application of a heated Iron to the Tube, as is practiced in the purging of it that way; and also for that Polish Iron will rust though immersed in it, as some Philosophers have lately observed. Now whether the Quicksilver rises in the Pipe (which it certainly does in hot, and frosty weather) it may then be said to be in a Natural state, free open and expanded like itself, which it seems it ever is within the Tropicks, and with us only in very hot, and very frosty weather. But when it descends, it is then contracted, and as it were convulsed and drawn together, as it mostly is in our Climate of England, and more or less, as we guess; in all places on this side the Tropicks. Which contraction plainly appears from the Concave figure of both Superficies, not only in that of the Quicksilver in the Tube, but also (if well observed) in that which stagnates in the Pot, or Dish itself. The difficulty seems to lie in the reconciling the same effect of the Quicksilver's rising in the Tube, from such seemingly differing causes, as great heat and intense Frost, and those who shall willingly assent to us in one particular, and grant us warmth, as a probable cause of its Restitution to its Nature, will yet be at a stand, how to imagine, that great Frost likewise should bring the Quicksilver nearer its own Nature too; I answer, that Salts liquified will coagulate or Cristallize, that is, will return to their own proper Natures, both in Cold and in Heat; and therefore tho most men practice the setting them in a cool Celler for that purpose, yet some (as Zwelfer) advise, as the best means to have them speedily and fairly Cristallized, is to keep them constantly in Balneo. Thus also the Lympha of the blood doth become a jelly, if you set it in a cool place, and the same is by warmth in like manner inspissated. Again that its no new Opinion, that water is naturally Ice, if no disquiet from some external accident hinder. * Bornichius the Learned Dane has said something for it; And although some may think, that what he hath said, was a meer Complement to his own frozen Climate: yet I dare venture to add, in confirmation of that Doctrine, that Salt is naturally Rock, that is, naturally Fossil, not liquid; And yet this is most like Ice of any thing in Nature; not only because of its transparency, but also for its easy liquefaction, and the sudden Impressions and changes which Air makes upon it; that its scarce to be preserved in its natural state of Cristallization. Also Salts of all sorts seem naturally to propagate themselves in a hard state, and to vegetate in a dry Form. The like is to be observed in Quicksilver, of its being a hard Rock, and also from its willingness to imbrace upon all occasions a more fixt State, as in its amalgamizing with almost all sorts of Metals. It will not be amiss by way of Corollary (and indeed it is one of the great uses too, of a Register of the Air) to add a Note or two about Healthful and Sickly seasons, more particularly as they may refer to this Phenomenon of great cold and Frost. If therefore Quicksilver and Liquids are nearest their own natures, and have less Violence done to them, in very cold and very hot seasons; The Humours of our Bodies, as liquids, in all probability must be in some measure accordingly affected. * Adelanie. And that therefore cold is healthful, I argue from the vast number of Old men and women to be found upon the Mountains of England, comparatively to what are found elsewhere. Again, the Blood it felt; or the Vital liquor of Animals equivalent to it, is in most kinds of Animals in Nature sensibly cold; for that the Species of Quadrupeds and Fowles are not to be compared for Number to Fishes and Insects: There being in all probability by what I have observed, above a hundred Species of these latter creatures whose Vital juice is cold, to one of the former: But because we most converse with those whose Vital Juice is hot, we are apt to think the same of all. Again I have observed, which I offer as an Argument of the little injury intense cold does to the nature of Animals, I say, I have seen both Hexapode-Worms (which I compare to the tender Embryos of Sanguineous Animals, because such are in a middle State) and Flies of divers sorts hard frozen in the Winter, and I have taken them up from the Snow, and if I cast them against the Glass, they would endanger the breaking of it, and make it Ring like so much hard Ice; yet when I put the Insects under the Glass, and set them before the fire, they would after a short time nimbly creep about, and be gone, if the Glass which I whelmed upon them, had not secured them. It hath indeed been noted by a very wise Philosopher in contradiction to our English Proverb *, which faies, that a Green Christmas makes a fat Church-yard; That the last Plague broke out here at London after a long and severe winter 1665. But I reply, that that was accidentally onely, for that that disease is never bred amongst us, but comes to us by trade and Infection. Tis properly a Disease of Asia, where it is Epidemical. And therefore by the Providence of God, we are very secure from any such calamities as the Natural effect of our Climate. And for the same reason, I judg the Small Pox too much * Ray's Proverbs. raging at present, not to be from the Season, or temperature of the year, but from Infection wholly; that also being an Exotic Disease of the Oriental People, and not known to Europe, or even Asia Minor, or Africa at all, till a Spice trade was opened the later Princes of Egypt, to the remotest parts of the East-Indies, whence it originally came, and where it rages more cruelly at this day than with us. The like I think of the Griping of the Guts, that it is a peculiar Disease of the West-Indies, and yearly received from thence, for this reason, that is none of the Tormina Ventris of the Antients, and therefore called by a new name, by such as have writ of it; and also for that it is yet scarce known in any part of the North of England, or Midland Countries thereof *. So that we are not to Judg or Prognosticate of the Salubrity or sickliness of a year, from foreign Diseases, but by the raging of such as are Natural to the men of our Climate. But enough of this, only this word to conclude, that if the most Elegant and learned Rivinus be in the Right, which I shall not here dispute, that fear is ever the prime cause of the plague †; 'tis fit to recommend its antidote; which is cheerfulness, and a reasonable security; that we are in no such danger from any Intemperature of the Air necessarily subsequent to so vehement a Frost. * Dr. Willis Dysenteria alba Londinensis. † Rivinus de Peste --Contagium non est contagium, nisi accedat terror -Sancto testor, me nullum lucusque vidisse egrum ex peste, qui non a terrore eam contraxisse.