152 THE MICROSCOPICAL NEWS, 
blotting paper, and mounted in Canada balsam. If the steps of 
the process have been properly carried out, the micro organisms 
will be found deeply stained. 
Great attention must be paid to the illumination of your objects. 
It is generally accepted that the best form of natural light is that 
from a white-cloud, and various forms of artificial white cloud, eg., 
plaster of Paris, ground glass, &c., have been constructed for use 
with artificial light. In selecting a lamp, for working by artificial 
light, care must be taken to see that the chimney, if made of glass, 
is free from striz and flaws. The best illumination which can be 
obtained is that from the most refined paraffin, and a half-inch 
wick. If you fail to illuminate your objectives properly; all their 
best qualities will be entirely lost. When I see at societies or in 
class-rooms, a single gas or oil lamp doing duty for two or three 
microscopes, I feel sorry for those who have to look at the objects 
displayed. He then proceeded to describe direct or central 
illumination, oblique illumination, and ‘the illumination of opaque 
objects, and in conclusion made some remarks on the binocular 
microscope and the polariscope. 
The simple binocular is an arrangement, whereby an exactly 
similar picture is thrown on to the retina of each eye, and is in 
reality a double monocular as no idea of solidity of form is con- 
veyed by it. In the stereoscopic and pseudoscopic binoculars a 
dissimilar picture is thrown on to each retina, so that the image of 
objects appears in relief. The pseudoscopic binocular is of hardly 
any practical utility and must be regarded in the light of an optical 
curiosity. Even with the lowest powers binocular effects are how- 
ever specially good with opaque objects, whether illuminated by the 
lieberkiihn or other illumination. As regards the polariscope, the 
best form of polariser is the Nicol prism, but whatever form is 
used it should be large so as to admit plenty of light, and placed 
below the condenser in the sub-stage. 
OUR SALMON FISHERIES. 
HE main result of Mr. Huxley’s study of the results of last year’s 
salmon fishing, as detailed in his report as inspector of the 
Salmon Fisheries of England and Wales, is a confirmation of the 
view that we really know little or nothing about the influences 
which regulate the salmon supply, and which are apparently much 
more complex and much less due to human agency than is generally 
supposed. Statistical societies would be able to deduce a variety 
of ingenious hypotheses from the published returns, but for that 
