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T E L E S CO P E S
1 An achromatic telescope by Dollond of 2 J-foot focal length, on a brass stand.
2 An achromatic telescope of about 50 inches focal length and 4 inches aperture,
with four different oculars, of which the magnifications are 186, 137?
75, & 24. The last magnification is used for the so-called cat-eye, to observe
comets, by J. van Deijl en Zoon, on a mahogany stand.
3 An achromatic telescope of about 10 inches focal length, by J. van Deijl en
Zoon, on a brass stand.
4 A binocular or arrangement of 2 complete equal and parallel telescopes, to
look with both eyes at the same time, by J. van Deijl en Zoon, on a brass
stand.
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CAMERA OBSCURAS
j 1 A so-called camera obscura in a small chest.
| 2 The apparatus of a large camera obscura, to be placed on top of a building,
with which is projected, on a table of plaster, what is happening in the
neighbourhood, being an accurate copy of the one placed in the observatory
at Greenwich; by Dollond.
Page *71
A R T IF IC IA L -E Y E S
j* 1 An artificial-eye, in which the various parts of the human eye are made of
glass and ivory.
| 2 An artificial-eye of brass and glass, serving to show the deficiencies of shortsightedness
and longsightedness, and how the same can be improved by
concave and convex lenses.
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MIRRORS
f i A flat metal mirror on a brass tripod. With it a wooden tripod on which the
same can be placed.
2 A concave glass mirror of 18 inch diameter, on a tripod.
j* 3 A glass mirror, on the one side concave and the other side convex, s Grave-
sande, CV, fig. 2.
4 A concave mirror suspended in a small cupboard to see the objects outside
the mirror, ’s Gravesande, CVI, fig. 6.
5 A convex, fully rounded mirror, in a wooden frame, in a sliding box.
6 A convex, fully round English mirror, smaller than the aforementioned, with
it six pictures glued to wood.
7 A prismatic mirror in a cylindrical tin case, and a similar, smaller one in a
flat case, with it 7 pictures.
8 A square needle-shaped mirror, with 7 pictures.
9 A cone-shaped mirror in a tin case.
These four mirrors are in a small mahogany chest.
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R E F L E C T IN G T E L E S CO P E S
x The Gregorian telescope of 2-foot focal length, with 4 different eyepieces,
magnifying 40, 90, 150, and 300 times, on a brass stand; by Dollond. With it
belongs a micrometer for measuring the diameters of heavenly bodies, and of
small distances. (The focal length of the lenses is about 40 feet); by Dollond.
2 A Newtonian telescope of 7-foot focal length; made by Herschel.
3 A telescope of ... inch focal length made by Dollond, in which is placed a
mirror of platina, from the Abt Rochon.
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A S T R O N O M Y
1 A celestial globe made by G. Adams in 1791.
2 A movable planetarium by G. Adams 1791J described and illustrated m
G. Adams, Astronomical Essays, London 1790, XVII.
3 A jovarium, or the system of Jupiter and its satellites, by G. Adams.
4 The system of Saturn and its satellites, by G. Adams.
5 An armillary sphere by G. Adams, Astron. Essays, XIII, fig. 2.
6 A universal equatorial instrument by G. [sic] Ramsden.
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G E O G R A P H Y A N D S E L E N O L O G Y .
1 A terrestrial globe by G. Adams in 1791, being a new construction with a
fixed axle. See on this an announcement in the Letterbode of 1792.
2 A t e l l u r iu m b y G. A d a m s 1791, A s t r o n . E s s a y s , XVIII.
3 A tellurium of a special construction, with a movable horizon, which can be
placed on the base belonging to it in the different positions of the orbit of the
earth; by Van Laun.
4 A lunarium by G. Adams 1791, Astron. Essays, XVIII.
5 A small globe of 6 inches diameter.
Page 76
N A V I G A T I O N
1 A sextant, by G. Hulst van Keulen.
2 An octant, by G. Hulst van Keulen.
3 An azimuth & gauge compass [fieilcompas], suspended in a mahogany chest,
by Kenneth McCulloch, London.
4 An azimuth and gauge compass [peilcompas], on which is an octant with a
telescope, for the observation of altitude, suspended in a mahogany chest, by
B. Ayres.