The Optical Glass Industry, Past and Present’ 
By Franois W. Giaze, Technologist, National Bureau of Standards 
[With 4 plates] 
The earliest lenses known to have 
been employed were probably hand 
magnifiers, as both Seneca and Aris- 
tophanes mention them. Quartz and 
glass lenses have been unearthed from 
the ruins of Nineveh, Pompeii, and 
Herculaneum. Ptolemy, A. D. 100, 
wrote a whole book on optics. 
A portrait, painted in 1352, shows 
two mounted lenses with handles 
riveted together, in front of the eyes 
of the subject. The invention of 
printing by Gutenberg, in the middle 
of the fifteenth century, stimulated 
the use of such spectacles; but, even so, 
it was not until 1760 that Benjamin 
Franklin invented the first pair of 
bifocal spectacle lenses. 
It seems likely that the increasing 
use of spectacles furnished the impetus, 
directly or indirectly, for the develop- 
ment of both the microscope and the 
telescope. Some authorities credit the 
invention of both instruments to 
Johann and Zacharius Jansen in 1590, 
while others give credit to Hans 
Lippershey or James Metius of Alk- 
maar for the creation of the telescope 
about 1608. In any case, between 
1590 and 1620, interest in the telescope 
developed rapidly. This early work 
on the telescope was with the refractor 
type of instrument. It was not until 
1670 that Sir Isaac Newton described 
to the Royal Society the first reflecting 
telescope and also demonstrated its use. 
1 Reprinted by permission from Sky and 
Telescope, vol. 6, No. 3, January, and No. 4, 
February, 1947. 
However, a similar type of instrument 
had been described by James Gregory 
in his Optica Promota in 1663. 
Another type of reflecting telescope 
was invented in 1672 by Cassegrain. 
During the next 200 years many im- 
provements were made in optical 
instruments, thereby giving great im- 
petus to the search for better optical 
glass. Its quality was greatly im- 
proved by the discovery, in 1790, of a 
method of producing a glass chemically 
homogeneous and substantially free 
from imperfections such as “‘stones’’ 
and bubbles. This invention and 
much of its subsequent development 
must be credited to Pierre-Louis 
Guinand, a Swiss watchmaker, and 
his descendants and their associates. 
They found that chemical homogene- 
ity could be obtained by stirring the 
molten glass and also discovered 
means of annealing the resultant 
product. Later Guinand worked with 
J. Fraunhofer in Bavaria. The latter 
ultimately attained considerable suc- 
cess and produced telescope disks up 
to 28 centimeters (11 inches) in diam- 
eter. He further initiated the specifi- 
cation of refraction and dispersion in 
terms of certain lines of the spectrum 
and he even attempted an investiga- 
tion of the effect of chemical composi- 
tion on the relative dispersion 
produced by glasses in different parts 
of the spectrum. 
One of the associates of the Guinand 
family, Bonteps, was forced to flee to 
England in 1848 because of political 
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