131

Ian: 3. 1677/8.

Entred

mr. Henshaw vice president in the chair.-
mr. Wheeler former propounded by mr. charles Howard & Elected by Ballot
was this Day admitted -
The minutes of December the 20th. were read whereupon much . . .
Discourse was occasioned concerning the constitution of the air as to It transpa=
rency & opacousnesse Grauity & pressure, foggs, mists, & raines and wind.
concerning wch. It was Debated whether an opacous foggy or misty Air were
heauier than a cleer transparent air and it was concluded that the transpa
rency or opacousnesse of the air did not at all contribute to the grauity
or pressure thereof, though on the other side the extraordinary graui
ty of it might sometimes be the cause of its opacousnesse. And the Reason
was alledged, because sometimes euen when the pressure of the air was /hath been/ grea
test It hath been obserud that the air hath been as transparent and cleer
as at any other time whatsoeuer, and at other times when the air hath been
exceeding light foggs and mists haue been taken notice of. and that it was suppo
sed that the transparency and opacousness of the air proceeded only from the
vniformity of the parts of the air. and the opacousness from the difformity &
incongruity of them. That was thus Explaind by mr Hooke that the Aether that
Incompasses the earth was the grand or vniversall mentruum that ^ /Dissolued/ took vp
into Its self and suspended all sorts of vapours & exhalations whatsoeuer that
to witt all those bodys in the air Atmosphere which make vp or constitude that
body wch. hath a very great springinesse in it and wch. will not peruade the
pores of glasse but can be confind and excluded by it, much after the same
manner as water Dissolueth salt sugar or the like into self and keepeth it sus
pended & intimately mixed wth it, that soe long as these vapours and Exhalations
Remaine thus Dissolued and perfectly mixt & vnited wth. it they appear
perfectly transparent. But when by the mixture of Differing sorts of Vapours
they either vnite wth. them & Leaue the aether; or those other being more
congruous to the aether vnite & coalesse wth it & iostle out these and soe make
them a distinct body, these vapours or exhalations become as it were opacous tht
is though really they are in minimis as transparent as formerly yet by being
Disvnited wth the air and hauing a Differing transparency refraction they make
the air seem opacous & foggy. that these changes are often times wrought from
transparency to opacousness and from opacousnesse to transparency and yet the
grauitation of the air not at all altered. by reason that the same bodys remaine
suspended in the same part of the atmosphere, and consequently their grauitation
cannot be at All taken way. And whereas the vice President obiected that It was

Ref: CELL/RS/HF_133  © Centre for Editing Lives and Letters