A WORKING MICROSCOPE. 217 
again, the absence of a coarse adjustment in many of them may 
for some purposes be found inconvenient, while the fitting below 
the stage should be made removable. On the other hand, the 
short tube gives a larger field when used with the camera for 
photo-micrography, and is also more convenient as a dissecting 
microscope, lengthening as it does the anterior conjugate focus, 
and thus giving more room for the needles. 
Recognising these and several other advantages, the writer had 
an instrument constructed after the pattern shown in fig. 44. The 
draw-tube is wide enough to take the full size Ross eye-pieces, 
and when it is fully extended the whole forms a body of ordinary 
length. The stage, together with the body, is made to move round 
the optical axis as a centre, though this is perhaps unnecessary for 
most purposes. There are coarse and fine adjustments, a dia- 
phragm in the thickness of the stage and plane and concave 
mirrors, 
When standing vertically, and closed down the upper end of the 
eye-piece is eleven inches from the table, the collar in which the 
body slides is three inches in length, and lined with velvet. The 
body is 5 inches long, and the draw-tube 4? inches, with a 
diameter of 1.3 inches, the mirrors are 2.2 inches in diameter, 
and the fine adjustment raises or depresses the entire body ,j,th of 
an inch for each revolution. 
Of course we are perfectly aware there is no universal guage for 
eye-piece diameters or for substage fittings, It is a thousand pities 
that the Council of the Royal Microscopical Society do not bestir 
themselves in the matter, having done such good work in years 
gone by, in the direction of the universal screw for objectives. 
We would like to see all our leading makers producing a 
microscope stand to take their full size eye-pieces on the lines we 
have indicated. Such an instrument might be sold for six pounds, 
together with an A eye-piece, including also an adapter for those 
who wish to use continental eye-pieces. A microscope of this 
kind we would be always willing to recommend, serving as it would 
for years of work with low and medium power objectives. 
