187
Aprill the 4th. 1678.
The President S
r. Ioseph Williamson Present tooke the chair
The notes of the La
st Day being Read. m
r Henshaw, vpon the mention
of the way of sounding the Depth of the sea, a
sserted that /in/ Cardin
all Cu
sanus there was another way of sounding the Depth of the sea then
tho
se w
ch. had been Described by m
r Hooke /both/ by the help of a pipe
. . . and also by the Di
scent of a ball sunk by
a weight, which weight Leauing the Ball when it came to the bott
othe Ball a
scended w
th. the same velocity vpwards, w
ch. the weight
and Ball together De
scended w
th to the bottom.
Herevpon m
r. Hooke Explaind the particular contriuance of the
applycation of the Leaden weight to the Ball which he had
contri /inuented/
ued and made v
se of being the same w
ch. Remaind vpon the
Regi
ster of the Society, as also he shewd the vncertainty and
Inconuenience of the other contriuance. he hauing Experimen
=tally found that the same would often fail of performing the
De
sired effect. Either by Leauing each other before they came
to the Bottom, or not separating at all when they came thither
The President, m
r. Henshaw & m
r. Hill made seuerall obiections
again
st the way of sounding the Depth of the Sea by the aforesaid
contriuance w
th. a ball sunk by a weight the cheif of w
ch were foun
ded vpon the supposition of Galileo that De
scending bodys did accele
rate their motion continually in a duplicate proportion to the time
of their De
scent and therefore it seemd hard to conceiue how the
theory propounded by m
r Hooke should hold true to wit that the time
of the De
scent and a
scent of the Ball was always in the same
proportion w
th. the Depth of the Sea be it more or Le
sse prouided
it were
vp aboue two fathoms Deep. the Reason of w
ch. he alledged
to be that by pa
ssing about two fathom in the water the said ball both
in a
scending & De
scending would arriue to its Greate
st degree of ve
locity. The President Further vrged that both Galileo Ga
ssendus & mer
sennus had all affirmed the same thing that all De
scending did accele
rate their motion in proportion to the squares of the times, of
their continued De
scent. and that they had vpon this supposition been
at the trouble to calculate the time that a body would spend in
Di
scending to the center
To w
ch m
r. Hooke answered that tho
se callculations had been made
vpon a theory and not vpon Experiment for that Experiment would
euidence the contrary, And though in a vacuity of Water, air, or any
Ref: CELL/RS/HF_189 © Centre for Editing Lives and Letters
