ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
475 
MICROSCOPY. 
a. Instruments, Accessories, &e.* * * § 
(3) Illuminating and other Apparatus. 
Method of Indicating the Magnification in Drawings. j — M. Ch. 
Janet, referring to Dr. D. Carazzi’s note on the indication of magnifi- 
cation, l explains the method which lie employs when the drawings are 
not made with the aid of the camera lucida. He replaces the ordinary 
eye-piece micrometer by one ruled in squares, of which the sides arc 
O’ 5 mm. long, and draws on a piece of paper also ruled in squares. 
Knowing by a table made once for all what is, on the object examined, the 
lineal dimension corresponding to the side of the squares of the micro- 
meter eye-piece, he chooses the size of the square on the drawing-paper, 
so that all the details necessary can be conveniently introduced into the 
drawing. 
(6) Miscellaneous. 
Practical Microscopy.§ — The microscopist who is acquainted with 
the literature of his subject, or what passes for such, will remember that 
a book bearing exactly the same title as the present, except that it was 
called a new and revised edition, was published in 1889. Those who 
made themselves acquainted with that production of Mr. Davis know that 
there was much in it which could hardly be said to be up to date at the 
time of publication. So far as we can see, the differences between the 
two volumes before us lie in the title which is given to the edition, and 
in the advertisements which are to be found on the covers. The mis- 
prints of the edition of 1889 are, so far as we can see, accurately repro- 
duced in the edition of 1895. The same ignorance of the conventions 
of microscopists or of the elements of the Greek language which are 
indicated by the use indifferently of micra for micron and of micras for 
micra are here again well in evidence. We need not stop to point out 
that a work which was unsatisfactory and not up to date in 1889 is hardly 
one that is worthy of reproduction in 1895. 
Optical Institute of Zeiss in Jena.|| — Dr. M. Doll gives an account 
of the development of the Optical Institute of Zeiss in Jena. It was 
founded in 1846 by the late Dr Carl Zeiss. In 1866 Prof. Abbe 
joined the establishment, and has now, since the death of Dr. Carl Zeiss, 
in 1888, become the chief manager. From small beginnings the 
Zeiss establishment has become at the present time the largest firm for 
the supply of purely scientific instruments in and out of Germany. 
In 1880 larger premises were built. With a staff of over twenty 
scientific officers, the number of workmen now numbers 450. The glass 
factory in connection with the optical institute was a creation of 
* This subdivision contains (1) Stands ; (2) Eye-pieces and Objectives ; (3) Illu- 
minating and other Apparatus; (4) Photomicrography; (5) Microscopical Optics 
and Manipulation ; (6) Miscellaneous. 
t Zool. Anzeig., xviii. (1895) pp. 259-60. J See ante, p. 368. 
§ ‘ Practical Microscopy,’ by George E. Davis, 3rd and revised edition, London, 
1895, 8vo, 436 pp., 310 figs, in text. 
|| Centrul-Ze.t. f. Optik u. Mechanik, xvi. (1895) pp. 98-9. 
