39

mr Hooke was orderd to shew the Company such pearl coloured glasse as he made formerly
There were tryed 2 wooden circular pendulums one after another hung by the edge one of 18 the other
of 9 inches Diameter, with a small pendulum of 3/4 of the Length of the Diameters of those
wooden Circles, and It was found that this small pendulum of the said Length was Isocrone
wth. the vibrations of those wooden Circles according to mor. Zulichem Rule.
Sr. W Petty Dr. Wilkins & Mr. Hooke were desired to Repeat by themselues in a very still Room
mr Zulichems Expt. for the vniversall measure. The Expt. made twice in Publique hauing va
ried from his Rule by 1/10 the first time and 3/20 the second
mr Hook was orderd againe to attend the Pret. at his house for adjusting the Pendulum
to vibrate seconds. It being doubted whether the note of the precedent meeting about that
particular was rightly taken. The same was orderd to make a short pendulum as best for keeping
the time exactly (breaking the nerues to the diaphragme.) volatill salts as of salarmoniac, vrine
& harts horne being mixed wth. the blood make it flored fluid & sweet. Soe S: Wine but without Light
in the Colour. oyle of turpentine preserues it sweet & its Colour But acid spirits as of salt and niter
immediately coagulates, and Renders the Colour of the Blood Dirty -
December 28: 1664 (obseruas of comet) Dr. Pells wooden hoop 20 inches broad. wth bleus
plates inuerted of the Ecliptick) An expt. was made wth a circular plain hanging by a string of 17 1/4
inch. the Radius of the circle 9 inches soe that the Distance from the center to the point of suspension
was 26 1/4 inch. which being calculated by mr Hook according to his Rule gaue the distance of the
center vibration to the point of suspension of 27 3/4 inches whereas it should haue giuen
28 3/10 inches. mr Hooke acquainted the company that he had been adjusting at my Ld Brounkers house
the pendulum Vibrating seconds & that his Lop. and he though measuring by the same string
yet could not determine the exact Length, because the string broke which made them differ
The Ld Brounker finding 29 inches wanting 1/20 but mr. Hooke 29 1/20 inches. The same brought
in his obseruations of the comet on Dec: 23 in writing, whence he concluded that this was
the same starr that had appeared about a week, he added that it seemd to be a body that
was dissolued in the aether, and that the parts that were dissolued did ascend from its
body directly opposite to the sun or from the grauitating Center of the Planetary system
After a like manner as a smoke from a Burning body does ascend vpwards from the
center of the earth he exhibited also a scheme of the hypothesis whereby he conceiued
that all the irregular motion of the starr towards the west which hitherto it had been obserued
to make could be explicated vzt by the motion of the earth with out ascribing any or
very Little motion to the comet he was orderd to continue his obseruations with all diligence
and Exactnesse, and to see whether they and those of others would agree wth the said hy
pothesis, and to bring in a history of all in writing. (mr. Boyles expt. of breaking the
nerues) operators obs: of baroscope for 1 year. -
Ian: 4. 1664/5 (Obs: of comet). mr. Hooke shewd the way of applying a thermometer
to the weather clock, by sealing vp spt. of wine in a glasse cane with two pretty large head
whereof one was filld full wth Spt. of wine as was also the intermediat stem. the other not
quite full (a space of air being left to giue liberty for the Expanding. the cane thus filld
was poisd in the manner of the beam of a ballance, and the operation of the heat
& cold on it was that the heat expanding the liquor made it passe through the stem
out of the Ball perfectly full into the Ball wherein was left space of air; soe that heat
made the air ball Descend & cold on the other side condensing the liquor made it passe
out of the air Ball into the full Ball & soe made that to descend. It was suggested to
consider whether this instrument were sensible & nice enough. It was (vpon mr boyles
mentioning his Expt. of Cold) It was suggested Desired that those that could between this and next
day make any expt. of cold would make vse of this weather Especially Dr. merret & mr. Hooke
whereof the Later was orderd particularly to prepare a thermometer that may serue for a
standerd of heat & Cold by obseruing a degree of cold which Iust freezeth common Distilld
wall & by marking therevpon the Expansion of the liquors in the thermometer. (frozen carrets
mentiond) mr. Hooke made an Expt. tending shew As he conceiued that air is the vniuersall

Ref: CELL/RS/HF_041  © Centre for Editing Lives and Letters