SCIENTIFIC SUMMARY. 671 
As a rule, however, we are opposed to the “ multiplication by fission” process, 
which unhappily originates many of our scientific societies. 
A New Dissecting Microscope has been devised by Dr. Lawson, and manu- 
factured for him by Mr. Charles Collins. It is of the class of simple 
microscopes ; but is binocular, the lenses being semi-prismatic convex ones. 
The powers do not exceed six diameters ; but Dr. Lawson considers that 
in the dissection of the lower animals such powers — when binocular — possess 
the following advantages over the ordinary dissecting lenses : — 1st. That an 
abundance of room is left between the lens and the object, so as to admit of 
freedom of action of the operator’s hands ; 2nd. That the object may be easily 
and weU illuminated by means of the “ condenser and 3rd. That several 
structures situate at different levels are brought simultaneously into view.. 
DR. LAWSON’S BINOCULAR DISSECTING MICROSCOPE. 
The stage of Dr. Lawson’s instrument consists of an oblong trough of gutta- 
percha, in which small animals intended for dissection can be pinned under 
water. In the centre of this trough is inserted a small disk of glass, through 
which, from a mirror placed below the stage, a flood of light can be thrown 
upon transparent structures. Two ann-rests draw out on each side of the 
microscope, on which the wrists can be placed when the observer is at work. 
The upper and front portions of the case unfold upon the table, and display 
a series of scalpels, needles, scissors, &c., necessary for the dissection of 
animal tissues. When closed, the new binocular presents the appearance of 
an oblong mahogany box, about six inches long by three and a half wide. Its 
magnifying power is low ; but this is more than compensated for by the rehef 
which is given to the object under view, and the large amount of penetration 
which the glasses possess. 
MINING, METALLUKGY, AND MINERALOGY. 
The Mineral Wealth of Bolivia is, according to the statements of Vice- 
consul J oel, much vaster than is generally believed. This gentleman alleges 
that there are almost inexhaustible veins of lead and copper in the iiei^’h- 
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