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REPORTS OE SOCIETIES. 
Mrs. A. Browett gave an exposition of the first chapter of the second 
part of Mr. Herbert Spencer’s “First Principles,” entitled “ Philosophy 
Defined.” A discussion followed. 
BIRMINGHAM MICROSCOPISTS’ AND NATURALISTS’ 
UNION.—April 23rd. The Chairman presented to Mr. C. Beale, C.E., 
on the occasion of his leaving England, a handsomely bound copy of 
Longfellow’s Poems, with an illuminated address on the title page, as a 
testimonial of the esteem in which he was held, and in recognition of 
his many kindnesses to the Society. Mr. Beale having suitably replied, 
the following exhibits were made:—Mr. Evans, Trigonia gibbosa in 
Portland stone, also specimen of rhyolite from the Wrekin ; Mr. W. H. 
Bath, collections of marine algae from Weymouth and Bournemouth. 
Under the microscope, Mr. Collins showed a section of stem of dog 
rose through a spine; Mr. Hawkes, tetraspores of Callotliamium roseum 
and Dasya coccinea. —April 30tli. Mr. W. H. Bath presented a copy of 
his book, “ The Young Collector’s Handbook of British Birds : their 
Nests and Eggs.” Mr. J. Madison exhibited specimens of Helix pisana, 
from Guernsey ; Mr. J. Betteridge, specimen of dunlin, Tringa alpina, 
in full summer plumage, shot near Westheath ; also a specimen of 
common tern, Sterna fiuviatilis, from Harborne. Mr. J. A. Green then 
read a paper on “ The Polarization of Light.” The writer said the 
term polarization was a description of any cause which produced two 
opposite or antagonistic states. It would be necessary to take into 
consideration the normal condition of light before we could understand 
the changes that took place. Light was compound in its nature, and 
was seen analysed in the solar spectrum. The structure of the Nicol’s 
prism was described, and how it divided the two rays, reflecting one 
and refracting the other, and the arrangements for adapting them to 
the microscope were shown. The paper concluded by referring to the 
use of polarized light in the study of mineralogy, chemistry, and other 
sciences.—May 7th. Mr. Deakin exhibited specimens of butterflies, 
from British Burmali ; Mr. J. Madison, specimens of Helix cartusiana , 
Clausilia itala, Pupa fruinenturn, and other shells, from Italy ; Mr. 
Barradale, cotton pods, from Ceylon and China ; Mr. J. W. Neville, a 
series of objects illustrating the development of Nepa cinerea from the 
egg to the imago.—May I4tli. A lecture was delivered by Mr. T. H. 
Waller, B.A., B.Sc., on the “Micro-Chemical Examination of 
Minerals.” The speaker said that when you examined a thin section 
of rock, owing to the crystals being seen in section, there was some 
difficulty in making out its constituent parts, although a judicious use 
of the polariscope would distinguish grains of quartz from hornblende. 
It therefore became necessary to adopt some more certain method. 
The pulverization and sifting of minerals was unsatisfactory, and their 
chemical analysis was very difficult. The lecturer said very good and 
certain results could be obtained by means of flame reactions with a 
Bunsen’s burner. A number of experiments were made showing the 
effects of soda, potash, and lime felspars on the flame, and the effects 
produced enabled the observer even to approximate to the proportion 
of the alkalies. In addition to this mode, solutions must be made by 
dissolving the minerals and crystallizing them under the microscope, 
when the results would throw further light on the subject. The 
lecturer concluded by saying that in the way he had pointed out a 
large amount of knowledge might be gained from a small piece of 
material, and very valuable aid obtained in the examination of rocks. 
At the close of the lecture, several solutions were shown crystallizing 
under the microscopes. 
