98 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
MICROSCOPY 
a. Instruments, Accessories, &c.* 
Cl) Stands. 
The Binocular Microscope of the Seventeenth Century.t — Mr. 
Charles E. West writes : — “ It is generally understood, I believe, that 
the binocular Microscope is a modern invention — that it goes no further 
back than the one made, about 1853, by Prof. J. L. Riddell, of the 
University of Louisiana. His instrument was a rude affair, made of 
two pieces of looking-glass, which was improved by Prof. A. K. Eaton, 
of this city, by substituting for the mirrors a solid prism of glass made 
of two triangular prisms which were cemented together. Riddell 
adopted the improvement. This is the basis of the modern binocular 
Microscope. Its perfection depends upon the equal division of the 
beam of light by the prism, or the uearness of that division into halves, so 
that the same amount of light may traverse each of the tubes to the eyes. 
I never used but one instrument that did this, and that was made by 
J. Zentmayer, of Philadelphia. I tried it on the P. angulatum with the 
1/5, 1/10, 1/15, 1/30, and 1/40 objectives, which resolved the frustule 
as satisfactorily as with a monocular. I have never found another 
binocular of this maker that would do this, and I have tried several. 
But the first inventor of the binocular seems to have been Antoni us 
Maria de Rheita, a Bohemian Capuchin, mathematician and astronomer, 
who published a work in 1645, under the title of ‘Oculus Enoch et 
Eli®, sive Radius Siderio Mysticus,’ a rare book, which I found in the 
Astor Library of New York. 
By a contemporary writer, R. P. F. Ioannes Zahn, who published an 
optical treatise in 1685, entitled ‘Oculus Artificialis Teledioptricus, sive 
Telescopium,’ there is given a minute description of de Rheita’s binocular 
Microscope and telescope. This work is in my possession, and from it 
I hope to prove that the binocular Microscope is no new thing. 
In a letter to his friend, J. Caramuelis, dated Cologne, 24th April, 
1643, de Rheita speaks of having detected most clearly, by means of his 
binocular telescope, ‘ with the greatest surprise, admiration, and delight, 
the sacred Sudarium Veronic® sive faciem Domini maxima similitudine 
in astris expressum,’ in the sign of Leo, between the equinoctial and 
zodiacal circles. Zahn has given in his work a figure of our Lord’s head 
as pictured on the handkerchief of St. Yeronica. George F. Chambers, 
in his revision of Admiral Smyth’s ‘ Cycle of Celestial Objects,’ has 
given a reproduction of the figure, and characterized it a ‘ pious fraud,’ 
a.d. 1643. 
I propose to give a translation from the Latin of such parts of the 
‘ Oculus ’ as have a bearing upon the binocular Microscope, as follows : — 
‘ Since the distance between the eyes is not the same for all persons, 
first of all an artificer must ascertain this distance if ho wishes to con- 
struct a tube perfectly fitting any one person. This can be best ascer- 
* This subdivision contains (1) Stands; (2) Eye-pieces and Objectives; (3) Illu- 
minating and other Apparatus; (4) Photomicrography; (5) Microscopical Optics 
aud Manipulation ; (6) Miscellaneous. 
t Free. Amur. Soc. Micr., xii. (1S91) pp. 57-OG. 
