PROCEEDINGS OF THE SOCIETY. 
847 
drawing objects, although for accurate measurements it was perhaps not 
to be recommended. 
Mr. Nelson exhibited and made some remarks on a new Microscope 
by Mr. C. L. Curties. He began by remarking that for many years he had 
been strongly of opinion that the favourite Continental model, viz. that 
known as the Hartnack, was a design that was radically bad in many 
ways. The goal he aimed at was that our laboratories and schools 
should be furnished with Microscopes built on thoroughly sound 
scientific design, and of good English workmanship, instead of those 
built, as we may say, on haphazard design, with which, as every good 
microscopist knows, critical work is simply impossible. 
To this end he had had, at various times, no less than three Micro- 
scopes built, each embodying various improvements. The frequent ex- 
hibition of the first of these Microscopes, both at this Society and at the 
Quekett Microscopical Club, bore fruit, and English Hartnacks with 
rack-work coarse-adjustment became common. Later still this improve- 
ment was adopted on the Continent. 
The instrument exhibited had quite a novel origin. Some time ago 
Mr. Curties received an anonymous letter containing suggestions for 
the improvement of the model. These were adopted and embodied in 
this instrument. First, it is in all its parts of large size. The base is 
more extended and its height has been raised. (With regard to the 
size of a Microscope, Mr. Nelson suggested that it should be estimated 
by its height when in a horizontal position, a full-sized Microscope 
being one whose axis, when horizontal, is 10 in. from the table). It 
has a mechanical stage 5 in. in diameter, with 8/10 in. rectangular 
movement, and with complete rotation. The substage has rectangular 
and coarse and fine adjustments. The body extends from 5^-12 in. 
Spiral rackwork is fitted to the coarse-adjustments of both the body and 
substage and the draw-tube. Both the fine' adjustments have the Campbell 
differential screw. The body fine-adjustment is placed in front of the 
coarse-adjustment, so that it only carries the body. One of the new 
features is the solid Jackson limb which carries both the body and 
substage. The lower stage-plate is of great thickness and is firmly 
secured to brackets on the limb. The instrument is very massive and 
weighs 17 lbs. 
Kigid economy has been studied in the production of this instrument, 
so that all movements which are not considered essential in a full-sized 
instrument have been left out, such as rackwork and centering gear to 
the rotating stage, rotation to the substage, &c. If this were put 
forward as an ideally perfect instrument there are several points one 
would criticize, but taking the instrument for the purposes intended, he 
thought it eminently serviceable, and one with which excellent photo- 
micrographic work could be done. 
Hr. Dallinger said he had examined this instrument, and was so 
much in accord with what Mr. Nelson had stated that any remarks of 
his own would only be a repetition of what had been already said. The 
best means had been here adopted to make a thoroughly good instrument 
at a comparatively low price. 
Mr. Nelson also explained, by means of blackboard drawings, some 
