Chapter 15

6. Generally in setled and fair weather both of Winter and Summer, the _Mercury_ is higher, than a little _before_ or _after_, or _in_ Rainy weather.

7. Again, generally it descended lower after Rain, than it was before Rain.

[Sidenote: _It seems these were _Easterly_ winds._]

8. Generally also it falls in great winds; and somewhat it seem'd to sink, when I open'd a wide door to it, to let in stormy winds; yet I have found it to continue very high, in a long stormy wind of 3. or 4. daies.

9. Again, generally it is higher in an _East_ and _North_-wind. (_Cæteris paribus_) than in a _South_ and _West_-wind.

10. I tryed several times, by strong fumes and thick smoaks to alter the Air in my Closet; but I cannot affirm, that the _Mercury_ yielded any more, then might be expected from some increase of heat. Such as have exact _Wheel-Barometers_, may try whether Odors or Fumes do alleviate the Air.

11. In this Closet I have not in all this time found the extreamest changes of the Quicksilver to amount to more, than to 2¾, or to 2-7/8. inches, at most.

12. Very often I have found great changes in the Air, without any perceptible change in the _Barometer_; as in the dewy nights, when the moisture descends in a great quantity, and the thickness sometimes seems to hide the Stars from us: In the days foregoing, and following, the Vapors have been {158} drawn up so _Invisibly_, that the Air and Sky seem'd very clear all day long. This I account a great change between ascending and descending Dews and Vapors (which import Levity and Weight,) and between thick Air and clear Air: which changes do sometimes continue in the Alternative course of day and night, for a week or fortnight together; and yet the _Baroscope_ holding the same.

13. Sometimes (I say not often) the _Baroscope_ yields not to other very great changes of the Air. As lately (_December_ 18.) an extraordinary bright and clear day; and the next following quite darkened, some Rain and Snow falling; but the _Mercury_ the same: so in high winds and calms the same.

14. I do conceive, that such as converse much _Sub dio_, and walk much abroad, may find many particulars much more exactly, then I, who have no leisure for it, can undertake. To instance in one of many, _December_ 16. last, was a clear cold day, very sharp and strong _East_ wind, the _Mercury_ very near 30. inches high, about three in the afternoon, I saw a large black cloud, drawing near us from the _East_ and _South-East_, with the _East-wind_. The _Mercury_ changed not that day nor the day following; the Stars and most of the sky were very bright and clear till Nine of the Clock; and then suddenly all the sky was darkned, yet no change of weather happened; _December_ 17. the frost held, and 'twas a clear day, till about two of the clock in the afternoon; and then many thick clouds appear'd low in the _West_; yet no change of the weather here; the Wind, Frost, and Quick-silver, the same, _December_ 18. the _Mercury_ fell almost ¼ of an inch, and the sky and Air so clear and bright and cold with an _East-wind_, that I wondred what could cause the _Mercury_ to descend. I Expected, it should have ascended, as usually it does in such clear skys. Casually I sent my servant abroad, and he discovered the remote Hills, about 20. miles off, cover'd with {159} snow, This seem'd to manifest, that the Air, being discharged of the clouds by snow, became lighter.

15. I have seldom seen the change to be very great, at any one time. For, though I do not now take a deliberate view of my Notes, yet I wonder'd once to see, that in one day it subsided about ¾ of an inch.

16. Of late I have altered my Method upon the _Barometer_, observing it, as it is before my Eyes, all day long, and much of the night, being watchful for the moments of every particular change, to examine, what cause in the Air and Heavens may appear for such changes. And now my wonder is, to see, how slow it is, it holding most between the nine and twentieth and thirtieth inch of late.

17. I must now (_January_ 13. 1665/6) tell you, that the _Mercury_ stands at this time (as it did also yesterday) a quarter above 30. inches; yet both days very dark and cloudy, sometimes very thick and misty Air; which seldom falls out. For, for the most part, I see it higher in clearest setled weather, than in such cloudy and misty Foggs. This thick Air and darkness hath lasted above a week; lately more Cold, and _East_ and _North-East_ wind.

[Sidenote: _This seems to be wished, because the motion of the _Mercury_ may be more free in a wider Cane._]

_Thus far_ the Notes of this Observing _Divine_; of which Mr. _Boyle_, to whom they were also communicated, entertains these thoughts, that they seem to him very faithfully made, and do for the main, agree well enough with his observations, as far as he remembers, not having them, it seems, at that time, when he wrote this, at hand; and though it be wished by him, that the Observer's Glass-Cane had been somewhat bigger; yet his diligence in fitting it so carefully, or rather so skilfully, as is above-mentioned, is much by him commended. {160}

* * * * *

_Some Observations of _Vipers_._

A curious _Italian_, called _Francesco Redi_, having lately had an opportunity, by the great number of Vipers, brought to the _Grand Duke_ of _Toscany_ for the composing of _Theriac_ or _Treacle_, to examine what is vulgarly delivered and believed concerning the Poyson of those Creatures, hath, (according to the account, given of it in the French _Journal des Scavans_, printed _January_ 4. 1665/6) performed his undertaking with much exactness, and published in an Italian tract, not yet come into _England_, these Observations.

1. He hath observed, that the poyson of Vipers is neither in their _Teeth_, nor in their _Tayle_, nor in their _Gall_: but in the two _Vesicles_ or _Bladders_, which cover their teeth, and which coming to be compressed, when the Vipers bite, do emit a certain yellowish Liquor, that runs along the teeth and poysons the wound. Whereof he gives this proof, that he hath rub'd the wounds of many Animals with the _Gall_ of Vipers, and pricked them with their _Teeth_, and yet no considerable ill accident follow'd upon it, but that as often as he rubbed the wounds with the said yellow Liquor, not one of them escaped.

2. Whereas commonly it hath hitherto been believed, that the poyson of Vipers being swallowed, was present death; this _Author_, after many reiterated Experiments, is said to have observed, that in Vipers there is neither Humour, nor Excrement, nor any part, not the _Gall_ it self, that, being taken into the Body, kills. And he assures, that he hath seen men eat, and hath often made Bruit Animals swallow all that is esteem'd most poysonous in a Viper, yet without the least mischief to them. Whence he shews, that it needs not so much to be wondred at, that certain _Empiricks_ swallow the juyce of the {161} most venomous Animals without receiving any harm thereby; adding, that, which is ascribed to the vertue of their _Antidote_, ought to be attributed to the nature of those kinds of Poysons, which are no poysons, when they are swallow'd, (for which Doctrine he also alledges _Celsus_) but onely when they are put into wounds. Which also has been noted by _Lucan_, who introduces _Cato_ thus speaking;

_Noxia serpentum est admisto sanguine pestis,_ __Morsu_ virus habent, & fatum _dente_ minantur;_ __Pocula_ morte carent._

And what also some Authors have affirm'd, _videl._ That it is mortal, to eat of the Flesh of creatures killed by Vipers; or to drink of the Wine wherein Vipers have been drowned; or to suck the wounds that have been made by them, is by this Authour observed to be wide of truth. For he assures, that many persons have eaten Pullets and Pigeons, bitten by Vipers, without finding any alteration from it in their health. On the contrary, he declares, That it is a soveraign Remedy against the biting of Vipers, to suck the wound; alledging an Experiment, made upon a Dog, which he caused to be bitten by a Viper at the nose, who by licking his own wound saved his life. Which he confirms by the example of those people, celebrated in _History_ by the name of _Marsi_ and _Psilli_, whose Employment it was, to heal those, that had been bitten by Serpents, by sucking their wounds.

3. He adds, that although _Galen_ and many modern _Physitians_ do affirm, that there is nothing, which causeth so much thirst, as Vipers-flesh, yet he hath experimented the contrary and knows divers persons, who did eat the flesh of Vipers at all their meals, and yet did assure him, they never were less dry, then when they observed that kind of Diet.

4. As for the Salt of Vipers, whereof some _Chymists_ have {162} so great esteem, he saith, that it hath no _Purging_ vertue at all in it; adding that even of _All Salts_, none hath more vertue than another, as he pretends to have shew'd in an other _Book_ of his, _De natura salium_; which also hath not been yet transmitted into these parts.

5. He denies, what _Aristotle_ assures, and what _Galen_ saith to have often tryed, that the _Spittle_ of a _Fasting_ person kills Vipers; and he laughs at many other particulars, that have been delivered concerning the _Antipathy_ of Vipers unto certain things; and their manner of Conception and Generation, and several other properties, commonly ascribed to them; which the alledged French Author affirms to be refuted by so many experiments made by this _Italian_ Philosopher, that it seems to him, there is no place left for doubting, after so authentick a testimony.

* * * * *

_Advertisement._

The _Reader_ of these _Transactions_ is desired to correct these _Errata_ in _Number_ 8. _viz._ page. 132. line penult. read _Wine_ for _Lime_; and page 133. line 10. read _Thresher_ for _Trepher_, as some _Copies_ have it; and page 136. line ult. read _purifie_ for _putrifie_.

* * * * *

_LONDON,_

Printed for _John Martyn_ and _James Allestree_, Printers to the Royal Society. 1666.

{163}

* * * * *

_Num._ 10.

PHILOSOPHICAL _TRANSACTIONS._

* * * * *

_Munday_, _March_ 12. 1665/6.

* * * * *

The Contents.

_Observations continued upon the _Barometer_, or _Ballance of the Air_. A Relation concerning the _Earth-quake_ neer _Oxford_; together with some Observations of the sealed _Weatherglass_ and _Barometer_ thereupon by _Dr. Wallis_. A more full and particular Account of those Observations about _Jupiter_, that were mention'd in Numb. 8. An Account of some Books, lately publisht, _videl._ Mr. _Boyles_ Hydrostatical Paradoxes; _Steno_ de Musculis & Gladulis; _De Graeff_ de Natura & Usu Succi Pancreatici._

* * * * *

_Observations continued upon the _Barometer_, or rather _Ballance of the Air_._

These _Transactions_ being intended, _not only_ to be (by parcels) brief Records of the Emergent Works and Productions in the Universe; Of the Mysteries of Nature of later discoveries; And, of the growth of Useful Inventions and Arts; _but_ also, and chiefly, to sollicite in all parts mutuall Ayds and Collegiate endeavours for the farther advancement thereof: We shall begin this _Second_ year of our Publications in this kind (in which, for 3-moneths the Printing-presses were interrrupted by the publick Calamity) with a few more particular Observations upon the _Ballance of the Air_, as they are most happily invented and directed by Mr. _Boyle_; and deserve to be prosecuted with care and diligence in all places.

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.

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 {166} 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.

* * * * *

_A Relation concerning the late _Earthquake_ neer _Oxford_; together with some Observations of the sealed Weatherglass, and the Barometer both upon that _Phænomenon_, and in _General_._

This Relation was communicated by the excellently learned Dr. _Wallis_, as follows:

On the 19. of _January_ 1665. _Stylo Angliæ_ (or _Jan._ 29. 1666. _stylo novo_) at divers places neer _Oxford_, was observed a small _Earthquake_ (as at _Blechington, Stanton-St. Johns, Bril_, &c.) towards evening. In _Oxford_ it self, I doe not hear, that it was observ'd to be an Earthquake; yet I remember about that time (whether precisely then or not; I cannot say) I took notice of some kind of odde shaking or heaving I observed in my study, but did impute it to the going of Carts or Coaches, supposed to be not far off; though yet I did take notice of it, as a little differing from what is usual on such occasions; (and wondered the more, that I did not hear any:) But not knowing, what else to refer it to, I thought no more of it. And the like account I have had from some others in _Oxford_, who yet did not think of an Earth-quake; it being a rare thing with us. Hearing afterwards of an Earthquake observed by others; I looked on my Notes concerning my _Thermoscope_ and _Baroscope_, to see if any alteration considerable had then happened.

My _Thermoscope_ consists of a round large Glass, containing about half a pint or more; from whence issues a long Cylindrical neck of Glass, about two foot and a half in length, and less than a quarter of an inch diameter; which neck was _hermetically_ sealed at the top, to exclude communication with the External Air; but before the sealing of it, the whole Glass was filled with _Spirit of Wine_ (tinged with _Cochineel_, to make it the more discernable to the Eye) so warmed, that it filled the whole content of the Glass; but afterwards, as it cooled, did so subside, as to leave a void space in the upper part of the Neck. Which Instrument, so prepared, doth by the rising or falling of the tinged liquor in the neck (consequent upon the expanding or contracting of the whole liquor contained in it and the Ball below) give a very nice account of the Temperature of the Air, {167} as to _Heat_ or _Cold_: Even so nice, as that my being or not being in my Study I find to vary its hight sometimes almost a quarter of an inch.

My _Baroscope_, I call another Instrument for estimating the _Weight_ or _Pressure_ of the Incumbent Air, consisting of a long _Glass-tube_ of about 4. foot in length, and about a quarter of an inch Bore: which tube (_hermetically_ sealed at the one end) being filled with Quicksilver (according to the _Torricellian_ Experiment) is inverted, so as to have the open end of it immersed in Stagnant Quicksilver, contained in a larger Glass under it, exposed to the pressure of the outward Air: Out of which open end (after such immersion) the Quicksilver in the Tube being suffered to run out, as much as it will, into the Stagnant Quicksilver, in which that mouth or open end is immersed, there is wont to remain (as is commonly known to those acquainted with this Experiment) a Cylinder of Quicksilver suspended in the Tube, about 28, 29, or 30. inches high; measuring from the surface of the Stagnant Quicksilver perpendicularly; (but more or less, within such limits, according as the Weight or Pressure of the Air incumbent on the External Stagnant Quicksilver exposed to it, is greater or less:) leaving the upper part of the Tube void. (Both which Instruments being the contrivance of the Honourable _Robert Boyle_, they are by him more particularly described in his _Physico-Mechanical Experiments touching the Air, Exper._ 17. and 18. and in his _Thermometrical Discourses_, premised to his _History of Cold_.)

Now, according to both these Instruments, having kept a daily _Register_ of Observations for more than a whole year (saving when I have been for some short time absent from home) I find my Notes for that day to be these.

_January._ |_Thermoscope._|_Baroscope._ 1665/6. Day. Hour. | inches. | inches. 19. 8. Morn. | 14-1/16. | 29-1/2. Hard frost. Close. 4. Even. | 14-3/8. | 29-1/4. Hard frost. Cloudy. 9. Even. | 14-3/4. | 29-3/4. Rain. Wind 20. 8. Morn. | 15-1/4. | 28-3/4. Sunshine. Wind.

So that, there being in the morning (_January_ 19.) a hard frost (which began the day before about 4. of the Clock in the {168} afternoon (_Jan._ 18.) and continued (with us) till about 5. of the Clock in the afternoon of that day, _Jan_ 19. with some fierceness) and the weather, _Jan._ 19. being in the morning, close; and cloudy all the day, with little of Sun-shine; the Liquor in the _Thermoscope_ was very little raised, by 4. of the Clock afternoon, that is, but 5/16 of an inch (which, had the Sun shone, would, it's likely, have been near an Inch:) and after that time (or somewhat before) had there been no considerable change of weather, it would upon the Sun's setting have fallen (and probably so it did, till about 5. of the Clock, though I took no Observation in the interim.) But, contrary to what would have been expected, it was at 9. of the Clock at night, higher by 1/8 of an inch, than it had been at 4. occasioned by the change of weather, the Frost suddenly breaking, with us, between 5. and 6. of the Clock; about which time also it began to rain, and continued raining that Evening and good part of the Night. And the next morning I found the Liquor yet higher by half an inch, _vid._ 15¼ inches: (by reason of the Air that night being so much warmer, than it had been the day before;) whereas commonly it is considerably lower in the morning, than over night.

As to the _Baroscope_, for the Weight or Pressure of the Air; I find, that for the 11, l2, 13, 14, 15, 16, and 17. dayes, the _Mercury_ in the Tube, was (by the ballancing Pressure of the incumbent Air on the stagnant Quicksilver, exposed to it) kept up to the height of near 30. Inches above the surface of the External Quicksilver, (though with some little variation, as 30, 29-15/16, 29-7/8, 29-13/16 but never so low, all that time, as 29¾;) which is the greatest height I have know it at, (for I do not find that I have ever, till then, observed it to be, in my Glasses, full 30. Inches, though it have been very near it:) the Weather having been almost continually Foggy, or very thick Mists, all that time. _January_ 18. it came down to 29¾, in the forenoon; and afternoon, to 29-11/16. about the time the frost began: And _Jan._ 19. it was, at 8. in the morning, come down to 29½; at 4. in the afternoon, to 29¼. But at 9. in the evening (when the Earth quake had intervened) it was risen half an inch, _vid._ to 29¾. And, by the next morning, fallen again a whole inch, _vid._ to 28¾; which fall I attribute (at least in part) to the rain that fell in the night.