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he further added that he had a catalogue of such experiments
which he though he should haue occasion shortly to make in
order to the Elucidating of a theory wch. he Disigned shortly
to make publique hereafter. -

The vice President further inquired whether the Drynesse
or moysture of the air did not cause an alteration
of the Grauitating Power vpon the earth.
To wch. mr. Hooke affirmed that the Drynesse or moysture
of the air contributed not at all to the Grauity
or Leuity thereof but only the Greater or Lesser quan
tity of the Vapours held suspended by the aether in that
forme, and that whether it were in perfect air or
condensd into small globules of water wch. yet remained sus
pended it was the same thing prouided they remained -
suspended. And the

He further added an explication of what he vnderstood /meant/
by air said to be lighter & heauier in specie. to wit
that that air wch. had a greater quantity of Exhalation
in the same extention was the air that was heauier in
specie, and that wch. had a lesse quantity a lighter in
specie. And that the condensation or rarefaction of
the air added not at all nor took from its grauity
prouided the same quantity of Exhalations in the
whole cylinder.

The vice presid: Inquired further whether the air could
be made heauier in specie by any other cause than cold
to wch. mr Hooke answered that not only forcible con=
densation but severall fumes ^ /smokes/ and vapours wch. may be
raysd up into the air may produce that effect but that
It was very difficult to make it sensible by the Barometer

Ref: CELL/RS/HF_139  © Centre for Editing Lives and Letters