ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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of the problem has been sought also in the identical direction in which 
Dr. Abbe is working. More than a dozen years ago Charles A. Spencer 
told me of his own efforts, in the earlier part of his life, to manufacture 
new varieties of glass with the qualities now found in the Jena glass, 
but abandoned it because his pecuniary means were wholly inadequate 
to that sort of experiment. The liberality of the German Government, 
backing up the combination of high scientific acquirements of Dr. Abbe 
and his associates in the directions of physics and chemistry, has pro- 
duced the valuable results we see. A single consideration still holds 
back many investigators on this side the ocean from giving implicit faith 
to the new system, and that is the fear as to the durability and chemical 
stability of the new glass. There is, whether rightly or not, a strong 
impression that a too large proportion of the apochromatic lenses have 
been short lived, and some of the failures have been in the hands of 
such careful and skilful manipulators that careless handling cannot be 
assumed. To have a costly lens fail on one’s hands when the maker, 
who alone can be properly trusted to repair it, is on the other side of 
the globe, and custom house regulations are a practical veto on sending 
it back and forth, makes an earnest student of Nature pause. The 
same doubt seems to make American opticians cautious in using the 
new material, and it is hardly to be regretted that they should first 
exhaust the means of perfecting objectives made of the “old reliable 5 ’ 
flint and crown glass. In the hands of the average manipulator the new 
lenses do not show superiority over high-class American ones. The art 
of manipulating them (for it is an art) may well occupy some of the 
hours of the student, with the assurance that till he has acquired some 
skill in that way, he will not be able to detect the difference between 
tools having so nice shades of merit. And even then he may console 
himself that many experts agree with the opinion of Dr. Detmers, that, 
angle for angle, it cannot yet be said that the best European lenses excel 
the best American.” 
Ancient Lenses.* — Mr. Henry G. Hanks calls attention to a very 
old reference to lenses, or magnifying glasses, which he recently found 
in an old work, c The Vanity of Arts and Sciences,’ by Henry Cornelius 
Agrippa. The edition shown was an English translation, published in 
1676, from the original Latin edition, published in 1527. The reference 
alluded to reads thus : — 
“So we read, as Celius in his ancient writings relates, that one 
Hostius, a person of an obscene life, made a sort of glasses, that made 
the object seem greater than it was, so that one finger should seem to 
exceed the whole arm, both in bigness and thickness.” 
It was found that Caelius Antipater (to whom Agrippa probably 
refers) was a Roman historian who lived 125 years b.o. He wrote a 
history of the first Punic War, only parts of which were extant. So far 
as known, this was the first account of magnifying glasses in history. 
Henry Cornelius Agrippa, the author of this curious old book, was born 
at Cologne in 1486, and was a man of talents, learning, and eccentricity. 
In his youth he was secretary to the Emperor Maximilian, and was 
knighted for bravery in Italy. On quitting the army he devoted himself 
* Amer. Mon. Micr. Journ,, xi. (1890) p. 243. 
