502 General Notes. [ August, 
its concentrically swinging shutter, and in the radial arm he has talked 
about for years in connection with the aperture question, and he even 
made, two years ago, for Dr. G. Bacon, of Boston, a stand with an 
“accessory carrier ” swinging in this manner, but it does not seem to 
have been so formally published as to be available to the world or to 
constitute a claim to priority. In 1873 Mr. W. H. Bulloch, of Chicago, 
an optician who has made many excellent stands, constructed a large 
stand with the substage traversing around a point one tenth of an inch’ 
above the stage (to allow for thickness of object slide), but he did not 
combine the mirror bar with it, and does not now prefer to do s0. 
Although his model lacked the completeness, simplicity, and facility of 
management of the latest forms, he came very near accomplishing the 
result which has since been attained, and contributed an important step 
in the progress toward that end. He also made, as early as 1870, a mir- 
ror bar to swing above the stage for.using the mirror (without detach- 
ing it) for opaque illumination, and an identical device was employed 
by Spencer about the same time. Similar arrangements have been 
used by others, to say nothing of the common expedient of mounting 
objectives or other illuminating contrivances on a swinging arm on the 
stand or on a separate base for oblique illumination at various angles 
which have been employed by the writer and nearly everybody else 
interested, ever since the subject of oblique illumination became promi- 
nent. It is, however, true that such an adjustment never came ino 
general use as a tegular part of the stand, and it is nearly equally certain 
that it is now so established as an important and permanent improve- 
ment.” 
The following is Mr. Gundlach’s account of his invention :— 
“The construction of a stand with my now well-known fine adjust- 
ment, a modification of the glass stages used by many opticians, and 
finally the hanging of the mirror and other illuminating apparatus 1 the 
plane of the object, which had been already planned and announced 
before the close of the year 1875, was begun about the end of January, 
1876, in the factory of the Bausch & Lomb Optical Company, after m; 
arrangements with that company had been effected. In the congu a 
of that stand I had in view the employment of a solid glass stage (no 
open in the centre), expecting to gain thereby the advantage of very 
oblique illumination, in consequence of the refraction of the surfaces. ; 
“In order to obtain practically the optical object I had in view e 
placing the centre of rotation of the illuminating apparatus 10 the plane — 
of the object, I had to take this refracting power of the solid gan PE 
into consideration, and consequently had to place the central point © Z 
1 See Table of American Students’ Microscopes, by R. H. Ward, M. D., ie 
NaruraList for June, 1872. rmat 
2 The substance of this note was given in Dr. R. H. Ward’s address as chair ve 
of the n seopical sub-section of the American Association for the Advanceme’ 
of Science, at the Buffalo meeting last August. 
