621

Iune the 3d. 1691: Present the Prest: Sr. I Hoskins mr Henshaw Dr Slone Dr. Harewood
mr. Lodowick mr. Houghton. &c R Hooke


The President gaue an account of mr. Masters Loadstone - of wch. gaue a further ^ /& more particular/ account
is desired to be procured for some other meeting.------ Vpon the Occasion of mr. Hallys absence . . . . .
a Discourse about the Pressure of the air, ^ /and of/ the water &c. Some were of opinion that the pressure
of the water must render the breathing of a man vnder it more difficult especiall in the expiration of the :
by reason of its pressing into the lungs. others conceiued that the inspiration would be more difficult by Reason of the
water against ^ /the brest/ the ^ belly &c but vpon debating it was concluded that the air water or water without the tho[r]ax
by its pressure counterpoised the ^/comprest/ air in the Lungs & soe reduced all both to an equilibriu and soe the fear of
Difficulty of breathing was removed.

Next it was queryd how Whales or other liuing creatures could sustain the weight of soe great a pressure of wa
ter vpon their backs, as /that of/the a cylinder of water of equall base wth the Horizontall section of their body [&c]
1663 not be crushed against the bottom of the sea of the height of 4 score or 100 fathoms and yet not be crushed
flat against the bottom of the sea, to which it was answered that the pressure of the water at any De[pth be]
low the surface of it is always equall to the weight of the superincumbent quantity of it. but that pressure not
only downwards but vpwards & side wards. and consonent to this the water at any depth vnder the surface
it will rvn and issue euery way with equall power & velocity whether downwards sidewards or vpwards
soe that the whale by this meanes susteines a greater pressure from the water vnder it vpwards than from the
water aboue it downwards by the depth of the perpendicular thickness of its body. but as its induring the
pressure euery way against the air in its lungs it must be ascribed to the yealding of the parts of [Its bill. .&c]
to its naturall constitution & fabrick: since tis certaine ^ /1st/ that the ^ /wale/ doth oft diue to the bottom, and . . . . /2ly/ [. . ]t
he hath Lungs & doth breath, and ascertain /3ly/ that the air will be condensed proportionably to the pressure it
Lyeth vnder and as certain /4ly/ that the whale doth emerge again without being killed or hurt by it, it must therefore
necessarily follow that the belly & thorax must be contracted proportionaly to the condensation of the air in it Lungs
But yet that that air doth suffice for his life till he take in fresh at the top of the water.

Herevpon it was discoursed concerning the Difficulty of breathing when the pressure of the air is taken off, as the tops of very
high mountains, or in A Vessell wherein the air can be rarifyed in both which cases man and other animalls
are obserued to be much affected & Disturbed soe as to be sick & vomit & if the air be very much Rarefied to Dye
and vpon debating of it, twas concluded that as to the Disturbance at the tops of high hills, that the inconuien
ces proceeded partly from the thinnesse of the air and partly also from some noxious emanations from those hills
but as to the inconueniences felt in a vessell of Rarifyed air the/y/ inconvienences proceeded partly from the want of the
vsuall pressure of the air vpon the blood & humors of the body, which caused an expansion of some aeriall powrs
of those fluids, and partly from the want of a sufficient quantity of fresh air to supply the vita nourishment of the
vitall fire. which may easily be tryed by continually changing the air and yet keeping it vp to the same degree of
Rarefaction in the vessell. And as to the pain in the eares caused by a greater condensation or a greater rare
faction of the air than vsuall, that is plainly caused by the smallnesse of some passage between the outward
air and the Cauity of the coclia for that the paine did by degrees ware away as R Hook had tryed by the vessell
Long since made and tryed for that purpose by himself /before the Society/ by which also he found the Experience of remouing the
inconuenience of the want of fresh air. by forcing out the satiated air and admitting in of fresh. He had also shewed many
years since the most way how to preuent the same inconuenience in Compressed air at the bottom of the sea by a
sending down continually supplyes of fresh air by buckets or other vessells:

Ref: CELL/RS/HF_623  © Centre for Editing Lives and Letters