EOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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densers. By placing the forefinger on the holdfast a, the middle 
finger on the post of the spring clip c, and the thumb against the lowest 
corner of the sliding carriage, an object can be moved around and about 
the whole field of view, with the greatest facility and precision, and 
perfect control, while the other hand is constantly used at the same time 
in adjusting the focus as desired. Personally, I think such a carriage 
should be as light as possible, consistent with sufficient rigidity in con- 
struction. My own weighs only a little over one ounce ; the brass part, 
supporting the object slides C, being 1/25 in. thick, and that holding 
the broad glass rail A, double that thickness. The ledge against which 
the object slides lie, should, I think, be lower than their average thick- 
ness, to permit passing under high-power objectives so as to allow 
examination, even to the extreme edges. The ledge of my own carriage 
is 1/25 in. high, and I find this ample to securely support ordinary 
object-slides, and low enough to pass under the highest power ob- 
jectives. ’ 
The Society of Arts Microscope.* — The following is an account of 
the discussion on this subject which took place before a meeting of the 
American Microscopical Society last year. 
“ Prof. Claypole then read a paper on * The Society of Arts Micro- 
scope as a cheap Microscope.’ This instrument was designed and made 
forty years ago, and is still sold in England for about fifteen dollars. 
Mr. G. S. Woolman: What does Prof. Claypole consider cheap? 
Prof. Claypole: Twenty to twenty-five dollars. 
Mr. C. L. Griffith : What wages are paid by these Microscope- 
makers ? 
Prof. Claypole : I do not know ; we have no instrument made on the 
same plan. 
Mr. G. S. Woolman : I sold this instrument for many years at 22*50 
dollars. It is a miserable instrument. The American makers make 
much better ones for 30 dollars. 
Dr. Blackham : When I first commenced to use a Microscope I used 
one of these instruments. It is a little better than the Craig Microscope, 
or a drop of balsam in a pinhole. The lenses are not as good as a 1 *50 
dollar pocket magnifier — it is beneath contempt. The value of a stand 
is to hold the tube steady, and I would rather have a Jackson model and 
sliding-tube than that. The curious system of leverage it possesses 
magnifies every error of workmanship. The large model known as the 
Boss, which is similar to it, has been abandoned. The instrument I 
worked with was so badly made as to be worthless. Such traps are 
more likely to disgust a student with microscopy than to lead him on. 
Prof. Kogers : We have here two opinions — one that of an instructor 
who has successfully used the instrument in the class-room ; the other 
that of a dealer who formerly sold the instrument. It is only fair that 
both opinions should have their due weight. In regard to the choice 
between an instrument simple in form but of good mechanical construc- 
tion, as compared with a high-priced stand, I prefer the former. I use 
for most purposes a Bausch and Lomb stand costing about 12 dollars. 
It is well to keep in mind that nearly all the valuable work — e. g. in 
* Proc. Amer. Micr. Soo., xiv. (1892) pp. 32-3. 
