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The history of the camera obscura 25
the lively ymage of euery towne, village, etc., and that in as little or great space
or place as ye will prescribe, but also augment and dilate any parcel! thereof, so
that whereas at the firste apparence an whole towne shall present it selfe so small
and compacte together that ye shall not discerne any difference of streates, ye may
by applycation of glasses in due proportion cause any peculiare house or roume
thereof dilate and show it selfe in as ample fourme as the whole towne firste
appeared, so that ye shall discerne any trifle or reade any letter lying there open,
especially ifthe sonnebeames may come into it, as playnly as if you were corporally
present, although it be distante from you as farre as eye can discrye.
Digges does not describe the construction and we are left to presume that by 'frames'
he means tubes, and by 'due angles', the proper distance apart of the lenses. He continues
with a remark about the 'miraculous effectes of perspective glasses' -a term
which came to be used during the seventeenth century to denote a telescope.
The earliest reference to a small portable box camera is contained in Schott's Magia
universalis (1657). The Jesuit scholar KASPAR SCHOTT was another ofKircher's pupils,
and professor of mathematics at Wiirzburg. In the first part, 'Magia optica',32 which
was also published separately, Schott mentions in the fourth book, apropos ofKircher's
description already quoted, that he had been told of a much smaller camera obscura
seen by a traveller in Spain. It was so small that it could be carried under the arm and
under the cloak, and Schott comments that it is by no means necessary to have a
camera so large as to insert one's body or head, for it would perfectly suffice to look
through a small hole in the side. By way of practical demonstration, he made a little
camera obscura consisting of two boxes, one slightly smaller so that it could slide
within the other to adjust the focus (the type of camera, in other words, that was
used in the early years of photography). When this camera was fitted with an
adjustable tube containing two convex lenses, erect images were obtained.
By the middle of the seventeenth century tiny camera obscuras disguised as
drinking-goblets and books are mentioned. In the former the light rays entered
through a convex lens in the side of the stem of the goblet and were reflected by a
small mirror fixed in the stem at 45 ° on to the surface of the wine (which had to be
white). This amusing magic goblet, first mentioned by the French mathematician
Herigone33 and illustrated in Johann Zahn's Oculus, enabled a host unobtrusively to
keep an eye on his guests. Probably with the same idea of keeping watch, the
German schoolmaster J. c. KOHLHANS34 disguised his camera obscura as a book,
called opticum libellum.
In England ROBERT BOYLE wrote, in one of his tracts (1669),35 of a portable box
camera he had constructed. After describing how to render a piece of opaque paper
transparent by greasing it, Boyle says :
If a pretty large box be so contrived that there may be towards one end of it a
fine sheet of paper stretched like the leather of a drum head at a convenient distance
from the remoter end, where there is to be left a hole covered with a lenticular
glass fitted for the purpose, you may, at a little hole left at the upper part of the box,
see upon the paper such a lively representation not only of the motions but shapes
and colours of outward objects as did not a little delight me when I first caused this
portable darkened room, if l may so call it, to be made; which instrument I shall
not here more particularly describe because I showed it to you several years ago,36
since when divers ingenious men have tried to imitate mine (which you know was
to be drawn out or shortened like a telescope, as occasion required) or improved
the practice.