175

march 14. 1677 -

Entred

mr. Henshaw the Vice presidt. tooke the chair
vpon Reading the minutes of the last Day wherein it was supposd that the ouall
figure of might be caused by the velocity of its Dinatic . . .
turbinated or Diurnall motion of it vpon its own Axis mr. Henshaw obiected
that if it were soe why did it not always appear of that ouall figure when
it was seen at its greatest Elongation as well as when it was in coniunction
wth. the Sun. to wch. Sr. Ionas more answered /added/ that mr. Flamstead was of opinion
that it was causd by the refraction or badnesse of the glasse and proceeded from
mistake and not from any reall appearance since he could easily make it ap
pear soe wth. any glasse, and that there were many other mistakes in the
said obseruation and soe could not be Relyed vpon.

But mr. Hooke to both these obiections answerd first that the figure of
might be really allways soe ouall as mor. Gallet had affirmd to haue obseruedit and yet through the inaduertency of others it might not be taken
notice of, and possibly for want of as good glasses as those was it might
not haue been visible hereto fore. and to confirme this . . . /he said/ mor Gallet had
noted that euen in this obseruation through the 3 foot glasse it appeard Round
secondly the reasons why it may not appear Ouall in its greatest Elongation may be
3. first that it is very small and farr Distant & very bright all wch. doe make it
very difficult vnlesse wth very good glasses to see any figure at all of its body
but only a radiating point. Secondly that being seen . . . only part inlight
ned and neuer in opposition &c to the Sun the whole superficies of it seen
by vs is neuer all inlightned but only some parts of it which is a sufficient
reason to make it appear Round though the body of it be really ouall as is
supposed ^ /a part of this ouall being really not seen whereby the ouall is toournd into a circle/ for it must be a very good glasse by wch. one is able to Discouer the
true figure of when half inlightness by reason of its smallnesse & radiation
and it ought to be a very much better one to Discouer the figure of .
3ly. the figure of a dark body in a light medium is much better Discouerd than the
figure of a light body in a dark medium by reason of the Radiation -

next as to mr. Flamsteads supposition. mr. Hooke said that it was noe ways pro-
bable that a man that had made the whole obseruation wth soe much
care and wth. soe many witnesses, and besides had soe Ingeniously and knowingly
contriued the apparatus for obseruing it could either be Deceiued himself or Indea=
uour to Deceiue others. and therefore till there were better arguments than coniectures
or hypotheses against these circumstances of the obseruation we ought not to reiect or
condemn them.

vpon the mention of vsing long telescopes wth.out tubes seuerall obiections were
made as the bending of the lines the Difficulty raising it and fixed it and the
like but mr. Hooke affirmed he had actually done it that he had tryd Heuelius
his 90 foot glasse wth.out a tube. though it were afterwards tryed also wthout
a tube . . by mr Cox at mr Oldenburghs desire.

Ref: CELL/RS/HF_177  © Centre for Editing Lives and Letters