Selected quad for the lemma: blood_n

Word A	Word B	Word C	Word D	Occurrence	Frequency Band	MI	MI Band	Prominent
blood_n	air_n	cause_v	great_a	209	3	2.1268	3	false

Text snippets containing the quad

ID	Title	Author	Corrected Date of Publication (TCP Date of Publication)	STC	Words	Pages
A29057	Tracts written by the Honourable Robert Boyle containing New experiments, touching the relation betwixt flame and air, and about explosions, an hydrostatical discourse occasion'd by some objections of Dr. Henry More against some explications of new experiments made by the author of these tracts : to which is annex't, An hydrostatical letter, dilucidating an experiment about a way of weighing water in water, new experiments, of the positive or relative levity of bodies under water, of the air's spring on bodies under water, about the differing pressure of heavy solids and fluids.; Selections. 1672	Boyle, Robert, 1627-1691.	1672 (1672)	Wing B4060; ESTC R10383	110,756	442

the Hydrost Paradox And therefore there is no reason why the Divers bodies should be more forcibly depress'd than its depression is resisted 'T is true that this body will sink but that is because 't is not only as we lately suppos'd it aequiponderant to an equal bulk of water but heavier than that But then since the Water by its gravity and resistance takes off as much of the weight of the Divers body whilst that is immers'd as a quantity of water equal to it would weigh in the Air the subsiding of the humane body by its own weight ought to be but slow because that being not in specie much heavier than water it can sink but by virtue of the surplusage of weight that it has above water And in effect I have been informed by Swimmers that in the Sea whose water by reason of the Saltness is specifically heavier than the common water they could hardly dive when they had a mind the salt-water did so much support them And having because I had no conveniencies to make tryals upon the parts of humane bodies examin'd the weight of parts of other Animals in Air and Water I found the overplus of the weight of the animal substances above an equal bulk of water to be but very small And this may suffice to take off the wonder why though water be admitted to gravitate in water yet Divers are not depress'd by that which leans upon them the endeavour they use to keep themselves from sinking by striking the resisting water with their arms and legs easily compensating their weak tendency downwards which the small surplusage of gravity above-mentioned gives them But it seems to me far more difficult to render a reason why those that are a hundred foot beneath the surface of the Sea are not crush'd inwards especially in their chests and abdomens or at least so compress'd as to endure a very great pain To clear up or lessen this difficulty I have two things to offer 1. I confess that I am not intirely satisfied about the matter of fact for I do not yet know whether it fares alike with the Divers at all depths under water for according to the answers I obtain'd from persons that had been one of them at the Coral-fishing in the Streights and the other at the Pearl-fishing near Manar I do not find that the Divers are wont to descend to the greatest depths of the Sea which if they did perhaps they would find a notable difference And in small or but moderate depths those that dive without Engines usually make such haste or are so confounded or have their minds so intent upon their work that they take not notice of such lesser alterations as else they might observe especially they being persons void of curiosity and skill to make such observations Which I the rather mention because having met with a Learned Physician that living by the Sea-side in a hot climate delighted himself much in diving and inquiring of him whether he felt no compression when he passed out of the Air into the Water he answered me that when he div'd nimbly as others use to do he took not notice of it but when he let himself sink leisurely into the water he was sensible of an unusual pressure against his thorax which he several times observed A man that gets his living by fetching up goods out of wrack'd Ships complain'd to me that if with his diving Bell he went very deep into the Sea and made some stay there he found himself much incommodated which though he imputed to the coldness of the water yet by the symptoms he related I was inclin'd to suspect that the pressure of it upon the Genus Nervosum might have an interest in the troublesome effect And I have been assured by an eminent Virtuoso of my acquaintance that he was lately informed by a person whose profession it is to fetch up things from the bottom of the Sea by the help of a diving Bell that several times when he descended to a great depth under the surface of the water he was so compress'd by it that the blood was squeez'd out at his Nose and Eyes which Relation seems to favour our conjecture and would much more confirm it if I were sure that the effect was no way caus'd by some fermentation or other commotion in the blood it self occasioned by the great density or other alterations of the Air he breath'd in and out or by some other operation of the ambient Medium distinguishable from the compression of the water though perhaps conjoyn'd with it And on this occasion I remember that questioning an Ingeneer who had made use of an Engine to go under water quite differing from the Diving-bell he answer'd me that when he came to a considerable depth he found the pressure so great against the Leathern case wherein he descended and by that means against his belly and thorax that he feared it would have spoiled him which forced him to make haste up again But this observation to have much built upon it should be further inquired into These things and not these only make me wish that what is felt by those that dive to great depths and stay at them might be more heedfully observ'd by intelligent men that being fully inform'd what is true in point of fact we may the better and more chearfully indagate the reasons In the mean while taking things as they are thought to appear I shall propose two things towards the solution of our difficulty namely the Firmness of the structure of a humane body and the Uniformity of the pressure made by fluids Of the first of these I shall add but little to what has been already said where I spoke of the resistance made by our bodies to the compression of the Atmosphere only shall here take notice that whereas the Membranes are very thin parts and therefore seem unfit to make any great resistance we have tried that if a piece of fine Bladder were fasten'd to the orifice of a Brass-pipe of about an inch in Diameter we could not by drawing the Air from beneath it make the weight of the Atmosphere break the bladder though the weight were perhaps aequivalent to an erected Cylinder of water of the wideness of the orifice and about 30. foot high and we●e indeed such that divers men that laid their hands on the orifice when the Air was pump'd out from beneath complain'd that they were not able to lift off their hands again till some of the Air was readmitted But the main thing I shall propose towards the solving of the difficulty we are considering is the Uniformity wherewith fluid bodies press upon the solid ones that are placed in them And because I remember not to have met with Experiments purposely made to shew how this sort of pressure is more easie to be resisted than that of solids against solids I shall subjoyn the following tryals EXPER. I. IN the short Cylinder

the doctrine founded on those Phaenomena that if the Atmosphere could really exercise so great a pressure as we ascribe to it it would unavoidably oppress and crush all the bodies expos'd to it and consequently neither other Animals nor Men would be able to move under so great a load or subsist in spite of so forcible a compression This I readily grant to be a plausible Objection but I suppose the force of it will be taken away by the following considerations put together And first the power of pressing that we ascribe to the Air is not a thing deduced as too many other consequences in Physick are from doubtful suppositions or bare Hypotheses but from real and sensible Experiments And therefore since we have clear and positive proofs of the Pressure of the Air though we could not explain how Men and other Animals are not destroyed by it yet we ought rather to acknowledge our ignorance in a doubtful problem than deny what experience manifests to be a Truth As is generally practised in treating of the Attractive and other powers of the Loadstone which are freely acknowledged even by those that confess themselves unable to explicate them though if experience did not satisfie us of them they were liable to divers more considerable objections than any that is urg'd against the Pressure of the Air. Secondly but though it be not absolutely necessary that we should answer the above-recited Objection otherwise than by thus declaring that the Spring of the Air is not to be rejected for it yet we will endeavour very much to lessen it if not quite remove the difficulty before we put an end to the discourse I consider then thirdly that they that urge the lately mention'd Objection against the great Pressure of the Air seem not to be aware that we were conceived and born in places exposed to the pressure of the Atmosphere and therefore how great soever that pressure appear to be it ought not to crush us now since when we were but embryos or new-born Babes and consequently very much more weak and tender than we now are we were able to resist it and not only live but grow in all dimensions in spite of it If there were any place about the Moon or some other of the Celestial Globes that some Learned men fancy to be inhabited that has no Atmosphere or equivalent Fluid about it and where yet men could be generated a-new if one of those men should be supposed to be transported thence and set down upon our Earth there might be made an Experiment fitted for our controversie In the mean time I doubt that since Nature is not observed to make things superfluously strong such a humane body being not made to resist any weight or pressure of Air would be of so tender and compressible a make that it would easily be crushed inwards by our Atmospherical pressure And though we cannot give an instance of this kind yet we make tryals somewhat Analogous to it in our Pneumatical Engine For when we place water in our Receiver and pump out the Air that was above it there will be generated a multitude of bubles some of which when the Air is carefully withdrawn will be of a strange and scarce credible bigness these bubles being generated where the Air cannot press upon them these dimensions are so natural to them that if the Receiver be suppos'd not to leak nor other unfriendly accidents to intervene they would for ought we know last a good while since I have elsewhere shewn that the Spring of highly dilated Air did continue for many months and a bladder would for no less time continue blown and filled in our Vacuum by a little Air that was left in it when the ambient air began to be withdrawn from it And yet the large bubles above mentioned when once the outward air is suffered to come in upon them are thereby so violently compress'd that in a trice they shrink into dimensions too small to keep them so much as visible and if I could have succeeded in my Attempt of producing such living Bodies as I endeavour'd but did not expect in our Vacuum I suppose the success would have confirmed what I have been saying Fourthly but you will tell me that so great a weight and pressure as I assign the Atmosphere must needs make a man feel pain and if not otherwise dislocate some of the parts must at least press the whole body inward But first being accustom'd to the pressure from our very birth and even before it so early and long an accustomance hinders us from taking notice of it those pressures only being sensible to us that are made so by some additional cause which by making a new impression excites us to take notice of it So we are not sensible of the weight of the cloths we are accustom'd to wear and so a healthy man is not sensible of the heat in his heart because 't is constant there and the sentient parts of the heart have been still us'd to it whereas that heat often-times has been very considerable and when in living dissections a man puts his finger into the heart of an Animal which probably has a fainter or at least no stronger degree of heat than a humane heart he will feel in his fingers accustom'd to the Air a manifest degree of heat if they be but in their usual temper 2. I have elsewhere proved by Experiments that a cubick inch of Air for instance has as strong a spring as suffices to enable it to resist the weight of the whole Atmosphere as far as it is exposed thereunto for else it would be more compress'd than de facto it is And 3. I have also shewn that a very little portion of Air though it will much sooner loose its spring by expansion than a greater yet 't will resist further compression as much as a greater And 4. I have also shewn that in the pores of the parts of Animals whether fluid or consistent as in their Blood Galls Urines Hearts Livers c. there are included a multitude of Aereal corpuscles as may appear by the numerous bubles afforded by such Liquors and the swelling or expansion of the consistent parts in our exhausted Receiver 5. To this we may add that besides the Bones whose solidity is not questioned a much greater part of the humane body than is wont to be imagined does really consist of Membranes and Fibers and the coalitions and contextures of these and that these substances are by the Providence of the most wise Author of Things made of a much closer and stronger Texture than those that have not tried will be apt to think as I could make probable by the great force that Bladders will endure and the very great weight that Tendons of no great thickness will lift up or sustain and by other things that I shall not now insist on Lastly There is a far greater difference than men are wont to suspect