The President's Address. 29 
to appreciate the difficulties to be overcome^ and the admirable 
manner in which the task was accomplished. I have much 
satisfaction in adding that a medal was awarded to Mr. Peters_, 
as the award states,, for ingenuity of construction. The in- 
strument is now^ by permission of the Council of King^s 
College^ in their museum. 
The International Exhibition afforded an opportunity of 
comparing the microscope stands and glasses of English and 
foreign makers. In this competitive examination the English 
opticians fully maintained the supremacy which, by general 
repute, was assigned to them; indeed, anything nearer to 
perfection than a first-class microscope, as supplied by the 
principal London houses engaged in the manufacture of these 
instruments, can scarcely be expected. The makers, however, 
are not content to remain without striving still further to 
improve both stand and glasses. 
Messrs. Powel and Lealand now regularly supply a ob- 
jective, remarkable for clearness of definition, of large but not 
extravagant aperture. The demand for these glasses, I am 
informed, far exceeds the expectations of the makers : this I 
believe is, in great measure, owing to the fact that the com- 
bination allows sufficient space between it and the covering 
glass to render its use comparatively easy and agreeable, 
instead of merely possible. 
Mr. Eoss has greatly improved his microscope stand by 
various additions and alterations. The rotating stage is 
now only one third of its former thickness, and being well 
chamfered on its under side, there is a large increase of 
working room for all the illuminating apparatus used beneath 
the stage ; the mechanical stage has been also reduced one 
third of its former thickness. By the use of the same 
diameter of tube as that adopted by Messrs. Smith, Beck, 
and Beck, the whole of the sub-stage, with the apparatus 
fitting into it, has been very much diminished in bulk. This 
is also one more step towards uniformity of size in the 
fittings of first-class microscopes by the various English 
makers. Both the circular part of the main stage and also 
that of the sub-stage are graduated ; the former enables the 
instrument to be used as a goniometer, and the latter will be 
found very useful in investigations with polarized light. 
To the mirror has been added a double arm, for the more 
efficient resolution of lined objects by simple oblique light. 
The whole instrument has been reduced more than one 
third in weight, and as this has been accomplished by a simpli- 
fication of the construction, and reduction of unnecessary 
thickness in the upper and moving parts, its steadiness has 
thereby not been impaired* 
