G EOM ETR ICA L and GRAPHICAL ES SAY S:
C O N T A I N I N G
I. A feleft, Set of'Geometrical Problems; amongft thefe are fome very curious
v ones for dividing Lines and Circles with Accuracy.
If. A Defcription of thofe Mathematical Inftruments which are ufually put into a
Cafe of Drawing Inftruments, and many other new ones'fbr Geometrical
Purpofes.
III. A Defcription of the Inftruments ufed in furveying and levelling of Land.
IY. A Defcription of thofe Inftruments that have been contrived, to aflift the Artift
in delineating with Accuracy, and in true Perfpe&ive, the Outline of sk
Landfcap?, Building, or any other QbjefL
A lfo Preparing fo r th e P refix
A n E S S A Y o n V I S I O N *
So far as relates to the Ufe of Spe&acles, pointing out the Criteria, By wfti'cE;
every Perfon may judge when the Ufe of them will be beneficial,,
and how to chufe them without injuring the Sight.
T A B L E
O F
C O N T E N 1 S*
C H A P . I-
4 Concife Hiftorv o f the Invention and Improvements which A have been made upon the Inftmment called a Microfcope.
p. i .
C H A P . II.
O f Virion, of the Optical Effeft of Microfcopes, and of the
Manner of eftimating their magnifying Powers, p. 28.
Adams’s Lucernal Microfcope, p. 65.
Cuff’s double-conftructed ditto, p. 83:,
Culpeper’s Microfcope, p. 89.
Solar Microfcope for opake Objects, p. 921
Common Solar Microfcope, p. 99- '
Wilfon’s Microfcope, p. 103. Ellis’s ditto, p. 1101
Lyonet’s Microfcope, p. 1U- Withering’s ditto, p. 115.
Botanical Magnifiers, p, 117. Telefcopic Microfcope, p. u 8 .
CHAP.