ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
793 
has always been well known to many of us, who have from time to time 
availed themselves of its facilities for the discussion of current scientific 
topics, and of the assistance always obtainable there towards the prac- 
tical construction and improvement of microscopical accessories.” 
The late Mr. Joseph Zentmayer.* — The American Microscopical 
Society publish in their Proceedings the following abstract of an 
obituary notice of this celebrated optician, which originally appeared in 
the ‘ Journal of the Franklin Institute,’ December 1888. “ Joseph Zent- 
mayer, optician, whose name was known all over the world, w r as born in 
Mannheim, Baden, in South Germany, in 1826. He received a good 
education, and learned his trade as an instrument maker. At the termi- 
nation of his apprenticeship, and after having made his ‘ masterpiece,’ 
as is the custom among German mechanics, he travelled throughout 
Germany, working in the best establishments, and improving himself in 
the knowledge and use of scientific instruments. He was an ardent 
republican, and his natural love of liberty led him to take an active 
part in the agitation that had as its objects the establishment of republi- 
can institutions in Germany. 
He came to America in 1848, in the twenty-fourth year of his age, 
hoping to find a free scope for his notions of freedom in the Western 
Bepublic. Between 1848 and 1853 he worked for the best instrument- 
makers in Baltimore, Washington, and Philadelphia. 
In 1853 he began to make mathematical instruments in Phila- 
delphia at Eighth and Chestnut Streets with but one single lathe. The 
high character of his work and the boldness of his conceptions attracted 
the attention of leading scientific men. Among these the late Dr. Paul 
B. Goddard was practically drawn to him, and it was Dr. Goddard who 
persuaded him to make the first of his large compound Microscopes. 
This early effort was so successful that the Academy of Natural Sciences 
and many of leading physicians who required such instruments, pur- 
chased those of his make and discarded the heavy and yet unstable 
instruments of European manufacture. Once fully embarked in this 
enterprise, it seemed to absorb his attention, and many were the 
improvements that followed each other in rapid succession, not only in 
the stand of the Microscope, but in its objectives. At the present time 
there is not a maker of Microscopes in the world who does not use some 
of the important inventions of this Philadelphia mechanician. Duriug 
the war for the Union he furnished most of the Microscopes used in the 
Government hospitals, and he received the highest commendations from 
all the officers and other authorities for his work. 
In 1865 he invented his photographic lens. The story of his inven- 
tion of this photographic objective is very interesting. At the time when 
the Harrison globe lens was attracting attention, Prof. Coleman Sellers 
was requested to write a paper for the ‘ American Journal of Science and 
Arts ’ on the nature and advantages of the globe lens for the photographic 
camera. After this was published its writer consulted Mr. Zentmayer 
about the combination, and he said that it was quite possible to make a 
leus of two simple uncorrected concavo-convex or meniscus glasses, made 
thin and of proper curves, and that such a lens would be chemically 
* Proc. \mer. Micr. Soc., xiv. (1893) pp. 161-6. 
