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ried twelve Rowers, befides the Paffengers. It was: tryed in the River of Thames ; and one of the Perfons that was in that submarine Navigation was then alive, and told it one, that related the Matter to our famous Founder, the Honourable, and most Ingenious Mr. Boyl. As to the Liquor, Mr. Boyl faith, he difcovered by a Dostor of Physick, who married Drebeg's Daughter, that it was used from time to time when the Air in the fubmarine Boat was clogged by the Breath of the Company, and thereby made unfit for Respiration ; at which time, by unftopping a Vestfelfull of this Liquor, he could fpeedily refore to the troubled Air fuch a proportion of vital Parts, as would make it again for a good while fit for Respiration. The Secret of this Liquor Drebeu would never disclofe to above one Perfon, who himself affured Mr. Boyl what it was. Vid. Boyl. Exp. Phys. Mech. of the spring of the Air. Exp. 41. in the Digref. ThisStory I have welated from Mr. Boyl, but at the farne time much question whether the Virtues of the Liquor were fo effestual as reported. } And as too grofs, fo too rare an Air is unfit for Respiration. Not to mention the forced Rarefastions made by the Air-Pump, în the following Note ; it is found, that even the extraordinary. natural Rarefastions, upon the tops of very high Hills, much affest Respiration. An Ecclefiastical Perfon, who had visited the high Mountains of Armenia, (on which fome fancy the Ark restsd) told Mr. Boyl, that whilst he was on the upper part of them, he was forced to fetch his Breath oftner than he was wont. And taking notice of it when he came down, the People told him, that it was what happen'd to them when they were fo high above the Plane, and that it was a common Observation among them. - The like Observation the fame Ecclefiafick made upon the Top of ä Mountain in the Cevennes. So a learned Traveller, and curiotiš Perfon, on one of the highet Ridges of the Pyrenees, called Pic de Midi, found the Air not fo fit for Respiration, as the common Air, but he and his Company were fain to breath shorter and oftner han in the lower Āir. vid Phil. Tranfići. No. 63, or Lowthorp's Abridg. Vol. 2. p. 226. . . - Such another Relation the learned Joseph Acosta gives of himfelf and bis Company, that, when they pastëá the high Mounrains of Peru, which they call Periacaca, (to which he faith, the Alps themfelves feemedito them but as ordinary Houfes, in regard of high Towers,) . He and his companions were furprized with : extreme Pangs of Straining and Vomiting, (not without casting up of Blood too,) and with fo violent a Distemper, that be concludes he fhould undoubtedly bave died ; but that this lasted not above three or four Hours, before they come into a more convenient and naturat â'emperature of the Air. All which he concludes proceeded frem the too great Subtilty and Delicacy of the Air, which is not proportionable to humane Respiration, which requires a mere grofs and td.mpérate Air, Fid Boyl, ubi fupra. . . . .” "1 M : , ! - C. i IllS

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Thus it appears, that an Air too Subtile, Rare and Light, is unfit for Respiration : But the Caufe is not the Subtilty or too great Delicacy, as Mr. Boyl thinks, but the too great Lightnefs thereof, which renders it unable to be a Counterbalance, or an Antagonist to the Heart, and all the Muscles ministering to Respiration, and the Diafole of the Heart. Of which fee Book 4. Chap. 7. Note 1. - And as our Inability to live in too rare and light an Air may. discourage those vain Attempts of Flying and Whimsies of paffing, to the Moon, &c. fo our being able to bëar an heavier State of the Air is an excellent Provifion for Mens Occasions in Mines, and other great Depths of the Earth ; and those other greater Prefi fures made upon the Air, in the Diving-Bell, when wę descend into great Depths of the Waters. |- , . » (4) That the Inhabitants of the Air, (Birds and Infests,), need the Air as well as Man, and other Animals, is manifest from, their speedy dying in too feculent, or too much rarefied Air ; , of which fee the preceding and following Note 6. But yet Birds and Infests (fome Birds at leaft) can live in a rarer Air than Man. Thus Eagles, Kites, Herons, and divers other Birds, that delight| in high Flights, are not affested with thė Rarity of the Medium, as those Persons were in the preceding Note. . So Infests bear the Air-Pump long, as in the following Note 6. • (3) Creatures inhabiting the Waters need the Air, as well as other Animals, yea, and fresh Air too. The Hydrocanthari of all Sorts, the Nymphe of Gnats, and many other WaterInfests, have a fingular Faculty, and an admirable Apparatus, to raife their back Parts to the top of the Waters, and take in fresh Air. It is pretty to fee, for Instance, the Hydrocanthari come and thruft their Tails out of the Water, and take in a Bubble of Air, at the tip of their Vaginæ and Tail, and then nimbly carry it down with them into : Waters; , and, when that is spent, or fouled, to ascend again and recruit it. - So Fishes alfo, are well known to ufe Respiration, by pasing the Water through their Mouths and Gills. Bat Carps will live ont of the Water, only in the Air 3 as is manifest by the Experiment of their way of Fatting them in Holland, and which hath been prastifed here in England, viz., they hang them up in a Cellar, or fame cool Place, in wet Mofs in a fmail Ner, with their Head oụt, and feed them;with white Bread foaked in Milk for many days. This was w:msby a Person very sgrious, : - 4 - O

moft Animals live fcárce half a Minute (6); and others, that are the most accustomed to the want of it, live not without it many Days,

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of great Honour and Eminence, whose Word (if I had leave to name him) no Body would question : And it being an Infance of the Respiration of Fishes very fingular, and fomewhat out of the way, I have for the Reader’s Diversion taken notice of it.

(6) . By Experiments I made my felf in the Air Pump, in September and 0łłober, 1794 ; I obferved that Animals whose Hearts have two Ventricles, and no Foramen Ovale, as Birds, Dogs, Cats, Rats, Mice, &c. die in less than half a Minute counting from the very first Exfastion ; especially in a small Receiver.

A Mole (which I fufpested might have born more than other Quadrupeds) died in one Minute (without Recovery), in a large Receiver; and doubtlefs would hardly have furvived half a Minute in a small Receiver. A Bat (although wounded) fustained the Pump two Minutes, and revived upon the re-admiffion of the Air. After that, he remained four Minūtes and a half, and revived. Laftly, After he had been five Minutes, he continued gafping for a time, and after twenty Minutes I re-admitted the Air, but the Bat never revived. - * - *

As for Infests : Wasps, Bees, Hornets, Grafhoppers, and Lady-Cows feemed dead in appearance in two Minutes, but revived in the open Air in two or three Hours time, notwithstanding they had been in Vacuo twenty four Hours. . . - · · · · ·

The Earwig, the great Staphylinus, the great black lowfy Beetle, and fome other Infests would feem unconcerned at the Pacuum a good while, and lie as dead ; but revive in the Air, although fome had lain fixteen Hours in the exhausted ReCCIVGr.

Shells; two of which lay above twenty four Hours, and feemed not much affested. The fame Snails I left in twenty eight Hours more after a fecond Exhaustion, and found one of them quite dead,

but the other revived Frogs and Toads bear the Pump long, especially the former. A large Toad, found in the Houfe, died irrecoverably in lefs than fix Hours. Another Toad and Frog I put in together, and the Toad was feemingly dead in two Hours, but the Frog just alive. After they had 1 emained there eleven Hours, and stemingly dead, the Frog recovered in the open Air, only - - · : weak,

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And not only Animals themfelves, but even Trees and Plants, and the whole vegetable Race, owe their Vegetation and Life to this useful Element ; as will appear when I come to speak of them, and . is manifest from their Glory and Verdürė in a free Air, and their becoming Pale and Sickly, and Languishing and Dying, when by any means excluded from it (7). - - |

Thus useful, thus necessàry, is the Air to the Life of the animated Creatures; and no less is it to the Motion and Conveyance of many of them. All the winged Tribes owe their Flight and Buoyancy (8) to it, as shall be shewn in proper place : And even the watery Inhabitants themselvescannot

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weak, but the Toad was quite dead. The fame Frog being put in again for twenty seven hours, then quite died. A \ The Animalcules in Pepper-Water remained in Vacuo twenty four hours. And after they had been exposed a Day or two to theopen Air, I found some of them dead, fome alive. - - - - (7) That the Air is the principal Caufe of the Vegetation of Plants, Borelli proves in his excellent Book De Mot. Animal. Vol. 2. Prop. 181. And in the next Propofition, he affureth, In Plantis quoque peragi Aeris respirationem quandam imperfestam, à quâ earum vita pendet, & confervatur. But of this more, when I come to furvey Vegetables. Some Lettice-Seed being fown upon fome Earth in the open Air, and fome of the fame Seed at the fame time upon other Earth in a Glafi-Receiver of the Pneumatick Engine, afterwards exhaufied of Air : The Seed exposed to the Air was grown up an Inch and half high within Eight Days; but that in the exhausted Receiver not at all. And Air being again admitted into the fame emptied Receiver, to fee whether any of the Seed would then come up, it was found, that in the Space of one Week it was grown up to the Height of Two or Three Inches. Vid. Phil. Trans. No. 23. Lowth. Abriđg. Vol. 2. p. 2o6. - * * · · · · (8) In volucribus pulmones perforati aerem inspiratum in totam ventris cavitatem admittunt. Hujus ratio, ut propter corporis truncum Aere repletum, & quasi extenfum, ipfa magis volatilia evadant, faciliusque ab aere externo, propter intimi penum, fußententur. Equidem piftes, quò leviùs in aquis matent, in 4: Toe/104 s

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