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PROCEEDINGS OF THE SOCIETY. 
action extremely accurate and sensitive when severely tried. He had 
suggested to Messrs. Swift the advisability of clamping the body-tube, 
and the mechanical stage when the adjustments were made, and he 
understood the matter would be dealt with. 
Mr. E. M. Nelson said, as regarded the general stability of the whole 
apparatus, he could endorse all that Mr. Mayall had said about it ; but 
he thought it was obtained at too great a sacrifice, as the Microscope 
would have to he kept specially and wholly for photomicrographic work. 
He did not like the rotation of the Microscope with the wooden turn- 
table, for that seemed to him a lazy way of working ; he much preferred 
the standing position for making the adjustments. He knew of nothing 
more ridiculous than the picture in Zeiss’s catalogue of photomicro- 
graphic apparatus of a man sitting and adjusting the horizontal Micro- 
scope : such a position for work was quite absurd. There must be a rest 
for the arms, and unless a person was utterly decrepit, he should stand 
up to do work of that sort. He disapproved of Messrs. Swift’s arrange- 
ment of the focusing cord tightened by pressure of springs with pulley 
wheels. The cord should not be regulated by springs, but should be 
drawn quite tight by a screw arrangement; he estimated the proper 
degree of tightness in his own apparatus by its emitting a shrill note 
when tried by the finger. In this way he was certain of his focus. The 
plan of using indiarubber in contact with the milled head was quite a 
mistake, he had tried that and many other similar things, but they were 
all radically bad. The only really certain way of focusing from a 
distance was to use the tight cord he had mentioned. Another fatal 
objection was that the Microscope was not adapted for the use of Zeiss’s 
projection eye-pieces. He also criticized sundry points of detail in the 
arrangement of the camera, &c. He thought that with the springs taken 
away, and the other matters he had spoken of put right, the aj>paratus 
would be greatly improved. It was beautifully designed, and beautifully 
made, as all Messrs. Swift’s work was. 
Mr. T. F. Smith quite agreed with Mr. Nelson’s views. 
Mr. J. Swift said all the minor points referred to by Mr. Nelson as 
to the arrangement of the camera, the focusing screens, and sensitive 
plate-holders, really had been met, although he had not thought it 
necessary to bring everything forward at the meeting. He thought 
Mr. Nelson was mistaken in supposing there was only one way of 
arranging the focus from a distance successfully. He believed the plan 
adopted would be found efficient in practice. As to Mr. Nelson’s 
preference for a standing position in making the adjustments, it was not 
a matter for argument. The collimating arrangement at the end of the 
Microscope would be found useful, as it acted very readily and 
accurately where placed. Mr. Nelson was in error in supposing the 
tube had not been arranged to take Zeiss’s projection eye-pieces. 
Mr. Pringle brought him Zeiss’s achromatic condenser, and a projection 
eye-piece, so that there might be no mistake about their fitting properly 
on the instrument. 
Mr. Mayall observed that the collimating screw, as devised, moved 
the Microscope in relation to the lamp, so that it would require to be 
adjusted before the condenser was centered. He thought Mr. Nelson’s 
contention in favour of the standing position was hardly serious. He 
had worked with the Microscope for upwards of an hour, sitting on an 
