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Transactions of the Society. 
defect — one by Messrs. Swift, the other by Messrs. Zeiss ; but although 
these are great improvements they do not quite overcome the difficulty, 
and I urge upon those gentlemen and other makers and designers not 
to relax their efforts before complete success is obtained. Until that 
success arrives the inconveniences may be somewhat modified by a very 
simple contrivance, which, however, is rarely met with on our Micro- 
scopes. It is so simple that one hardly likes to mention it here, and yet 
it is very helpful. The slide should (and usually does) rest upon a sliding 
bar at the proximal side of the stage ; for the old plan of resting it on 
two pegs, so that when the end of the slide has passed one peg the 
slide tumbles off the stage, is now, I hope, happily superseded. At 
the left end of this sliding bar is a stop, which is most useful — indeed, 
almost essential — for measuring, finding, drawing, &c. ; but this stop 
prevents the slide being pushed on with the fingers when the move- 
ment of the mechanical stage is exhausted, before the end of the line 
of sections is reached. If this stop be hinged, and capable of being 
turned downward through an angle of 90 degrees, so that instead of 
being at right angles to the bar it forms an extension of it, the slide 
can be pushed along this extension, and the remainder of the row of 
sections seen. Of course, it is far inferior to a mechanical stage 
which will travel the whole distance, but it is a good deal better than 
nothing. The stop should have a little spring to cause it to stand 
firmly in these two positions and not between them. Anyone who 
has worked with this simple contrivance will appreciate the comfort 
of it as stages now exist. 
Another matter that I think does not receive as much attention 
as it might do in our Microscope-stands is the revolving stage. It 
is known how convenient it is for it to revolve right round; but 
this is very often neglected, or sacrificed to other things, and great * 
inconvenience is caused thereby. It does not usually matter very 
much while we are simply examining an object ; but when we come 
to draw it, we frequently find that we cannot turn the stage far 
enough to get it into the right position. Then the slide must be 
taken off* the stage and reversed, the object re-found, and the instru- 
ment re-focused (not without some danger of injury if the object be 
unmounted) ; and, after all, we perhaps find that we are not any 
better off, because the right position is just ’ that small piece of the 
circle which the stage will not pass, whichever side it be turned 
from. 
Another thing which, it seems to me, is too frequently neglected, 
is allowing sufficient space between the substage and the table for 
the mirror to be turned at any requisite angle when the Microscope 
is upright. And it is desirable that we should be able to turn it with- 
out (if we are using the flat mirror) reflecting the image of the milled 
heads of the apparatus which focuses the substage condenser, and 
throwing it on to the object. It is true that we can get rid of the 
image by turning the mirror ; but that limits the power of searching 
