790 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
council on tlie matter. They can only be made to move in a popular 
direction when they find such firms as Zeiss’s establishing themselves — 
as they are now doing — in London. 
Microscopists naturally want the highest class of optical appliances 
they can acquire with the outlay at their disposal. They feel that 
inferior means conduce to inferior results only. The demand for the 
improved instruments — apochromatic objectives, compensating eye-pieces, 
projection eye-pieces, &c. — exists. The supply of these novelties by 
English opticians has been so extremely limited, and withal so tardy, 
that it has amounted to nothing of any importance, so we have to rely 
mainly on Zeiss, of Jena. That great firm, employing some four hundred 
people, has now established two representative houses in London, and it 
behoves our opticians to look to their laurels, for the competition 
promises to be the most serious that has occurred during this genera- 
tion. Moreover, the competition will not be limited to the production 
of microscopical apparatus. The firm of Zeiss has now brought out a 
series of new photographic lenses which will, no doubt, demand and 
obtain the keenest attention of those who are interested in the progress 
of photography. — Microscopist.” 
“ In submitting the student’s Microscope, made by Messrs. Swift, at 
the last meeting of the Quekett Microscopical Club, I expressly dis- 
claimed any idea of novelty in the parts of the instrument. My sole 
intent was to show how easily some better form of centering fitting could 
be applied in place of the makeshift understage tube, which is, pace 
Messrs. Watson, after all, the only thing provided in the vast majority 
of students’ instruments. These gentlemen state that the form adopted 
by them in their Edinburgh model was designed by Dr. Edington, about 
two and a half years ago ; but Messrs. Crouch have, for a much longer 
period, made a very similar form, and so has Reichert, of Vienna. The 
great drawback, in my opinion, to this arrangement is that it is in the 
way when turned aside ; and, moreover, I do not think it can be con- 
tended that a substage supported by, and swinging on a single screw, 
is as steady and free from tremor as one with long bearings moving in a 
dovetailed guide. Mr. Nelson, whose criticism in these matters is 
always deserving of great respect, drew attention to the absence of a 
rack-and-pinion focusing adjustment in Messrs. Swift’s instrument, but 
one is very easily fitted if required, and for the class of work this 
instrument is intended for it is by no means necessary. 
I shall be very pleased if a discussion on this subject leads to the 
abolition of the non-centering substage tube, and the substitution of a 
more scientific arrangement, by whomsoever it may be designed. — 
George C. Karop.” 
“ When writing previously on this subject we had no thought of in- 
ducing a controversy ; but we must, in justice to ourselves, repudiate the 
inference of your correspondent, ‘ Microscopist,’ that the substage of 
the Edinburgh Student’s Microscope is not rigid. One would imagine, 
from your correspondent’s letter, that it is a useless arrangement ; but 
his information is evidently gleaned from the engraving that accompanied 
our previous letter, which he has not correctly interpreted, and certainly 
not from any practical working with one of our instruments. We would 
point out that when the substage is in the axial position, it fits into a 
