572 General Notes. [ September, 
purpose of lifting the object slide, when required, off the stage, the glass 
parabola is mounted in the substage in such a position that it can be 
raised by the substage rack until its upper surface is just above the level 
of the stage. The stand is arranged vertically, and a hair is placed in the 
stage forceps. For small objects a human hair is sufficient, but for larger 
ones a bristle is required, and it may even need to be slightly moistened 
when used, the object adhering while it is wet and falling off readily as 
it dries. If the hair is not easily held by the forceps, one end of it may 
be cemented between two small pieces of thick paper which are easily 
held. The slide containing the rough material is laid on the stage and 
the desired object selected and accurately centred; it is now, by the rack 
or sliding movement of the substage, lifted off the stage so as to be no 
longer affected by the stage movements. The end ofthe hair is next 
arranged just above the level of the object and centred exactly over it 
by means of the stage movements. ' Having got the end of the hair in 
the centre of the field, and having placed the object, dimly seen out of 
focus, below it, a slight elevation of the substage, which is still support- 
ing the slide, will bring the object in contact with the hair and leave it 
there when the slide is lowered again. A fresh slide can then be substi- 
tuted and brought up to the object on the hair, the exact position where, 
it shall touch being secured by the stage movements, if the substage has 
no centring adjustments. Where the substage has rotating and centring 
movements of its own the performance is most complete and accurate. 
It will be noticed that the principle of this method is the same as that 
of Dr. G. C. Morris,’ the novelty consisting in the excellent sugges- 
tion of carrying the hair on the stage forceps instead of on a special arm 
clamped to the stage. 
New Puaysicran’s Microscorr. — For convenience of those who 
prefer a stand of the compact, Continental model, the Bausch & Lomb 
Optical Company, of Rochester, have designed a new form of instrument 
which they call the physician’s microscope. In this stand Mr. Gund- 
lach has reproduced the Continental model so well worked out by him 
while in Europe, with several of the novel features of the Rochester 
styles, such as his new fine adjustment, the hard-rubber stage and mount- 
ings, and the new students’ series of objectives. 
Tin CELLS. — Prof. George F. Markoe, of 61 Warren Street, Bos- 
ton, Mass., has had a set of dies prepared with which he is now able to 
produce tin cells of various sizes and excellent quality. Microscopists 
can obtain these serviceable cells from him, by mail or otherwise, at a 
reasonable cost. i 
ExcHanGes. — Diatoms from coörongite, from South Australia, for 
good mounted objects. Address Galloway C. Morris, East Tulpehocken 
Street, Germantown, Philadelphia. 
Shell sand from the Bermuda Islands, for any really valuable aai 
1 See Arranging Diatoms, in the Narurarisrt for August, 1876, p. 502. 
