New experiments physico-mechanical, touching the air

The 40 and 41 Experiments.

But in his Animadversions upon these, having told the Reader that I seem to ascribe the sudden extinction of the in∣cluded Animals to the excessive thinness of the Air remaining

in the Receiver, made by the recess of what was drawn out, unfit for Respiration; he adds resolutely enough, Verum im∣possible videtur, ut hujusmodi animalcula ob solum defectum cras∣sioris aëris tam cito moriantur: But gives no other reason than that they dye so soon, which is no more than what he said in the newly-cited words, and besides is grounded upon some∣thing of mistake. For the Creatures he mentions were a Bee, a Fly, and a Caterpillar, and those included too in a small Re∣ceiver, which could be suddenly exhausted: and these indeed became moveless within a minute of an hour; but that minute was not (as the word is often us'd to signifie in English) a Moment, but the Sixtieth part of an Hour. And though these Insects did in so short a time grow moveless, yet they were not so soon kill'd; as appears by the Narrative. The sangui∣neous Animals that did indeed dye, were kill'd more slowly. And I remember that having purposely enquir'd of a man (us'd to go under water by the help of an Engine wherein he could carry Air with him to the bottom of the Sea) how long he could endure, before he was accustomed to dive, without breathing or the use of a Spunge; * 1.1 he told me, that at first he could hold out about two or three Minutes at a time: Which made me think that Divers become able to con∣tinue under Water so long, either by a pecu∣liarly-convenient Constitution of body, or by a gradual exer∣cise. And I am apt to think that he did, as men are wont to do, when he said two or three Minutes, mean what is indeed a much shorter time than that when exactly measured amounts to. For, having purposely made trial upon a couple of Moles that were brought me together alive, one of them included in a small, though not very small, Receiver was between two and three Minutes in killing; whereas the other being immediately after detain'd under Water did not there continue full a Minute and a quarter, before it finally ceas'd from giving any sign at all of life. By which trial it may appear, that 'tis not impossible that the want of Respiration should dispatch an Animal in as little

time as is mentioned in the Experiment I am now defending. And indeed our Author either should have proved that 'tis not possible for the want of Air to destroy Animals so soon, or should have given us some better account of the Phaenomenon. For whereas he teaches us, that according to his Doctrine the little Animals above mentioned were so soon kill'd, quia per ra∣refactumillum aërem sese contrahentem extractus sit corum halitus: I see not that hereby, if he explicate the Phaenomenon other∣wise than we, he explains it better; for he seems to speak as if he thought this halitus to be some peculiar part of the Animal in which his life resides. And besides he seems not to consider, that whereas, according to me as well as according to him, the Air contained in the Lungs (supposing these Animalcula have any) must in great part pass thence into the Receiver, (for whe∣ther that be done by the Spring of the Air it self, that was har∣boured in the Lungs, or the traction of the more rarefi'd Air in the Receiver, is not material in our present case) the Exami∣ner must, as well as I, render a reason why the extenuation or recess of the halitus should cause the hasty death of the included Animals; and condemning my Conjecture he ought to have substituted another reason: and though he subjoyns these words, and concludes with them, At{que} hinc quo{que} ortae sunt vehementes illae convulsiones, quas ante mortem passas esse aviculas quasdam memorat ibidem Author; yet I doubt not but the Rea∣der will think it had not been amiss that the Author had more intelligibly reduc'd these Tragick Symptoms from his As∣sumption, for the sake of those that are not Anatomists and Physicians enough to discern how his Funiculus could produce these effects.

For my part, as in the 41 Experiment I tender'd my thoughts concerning Respiration but doubtingly, so I am yet unwilling to determine resolvedly in a matter of that difficulty.

Notes

• * 1.1

  See more concer∣ning this Obje∣ction in the An∣swer to it as 'tis propos'd by Mr. Hobbs.