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be seen in the feeblest and most diffused light; but it is more specially 
adapted for the analysis of flames. A new form of spectroscope has also 
been described by Dr. Wolcott Gibbs, in the “American Journal of 
Science,” vol. xxxv., page 110. 
An abstract of a paper, “ On the Reflection of Light from Polished 
Surfaces,” by Rev. S. Haughton, F.R.S., has appeared in the “Proceedings 
of the Royal Society.” The following are some of the conclusions arrived 
at. That silver is the only substance which possesses the qualities of 
brilliancy and lustre. Of the metals which have high brilliancy and little 
lustre may be named mercury, palladium, zinc, alld iron. Of those which 
have high lustre and little brilliancy there are only two, gold and copper. 
A paper, entitled “ Some Remarks upon Light,” lias been read by Mr. 
B. S. Proctor before the Microscopical Society of Newcastle-upon-Tyne. 
The author shows that substances usually considered opaque, such as ordi- 
nary white lead, &c., are not so ; but that, as a rule, in white powders, 
pretty free transmission of light takes place through the individual par- 
ticles. He examines the question, why some substances, such as white 
lead, when mixed with oil, possess a greater “ body,” or opacity, than other 
substances, such as magnesia, which appear equally opaque in the dry 
state; and shows that, in the latter case, it is because the refractive power 
of the substance is nearly allied in degree to that of the oil, whilst in the 
former case it is very different, and with white lead much higher than that 
of the oil. The opacity of bodies was also further examined, and it was 
shown that no definite line could be drawn between transparent and 
opaque bodies, all were transparent in some slight degree when reduced to 
a very thin film ; and each then showed its own peculiar colour : thus gold 
and copper appeared green, silver violet or purple, arsenic brown, iodine 
red-brown, antimony and charcoal grey, &c. 
Mr. H. Treppass has exhibited at the Royal Institution a new optical 
instrument, called a charimorphoscope. It contains improvements upon 
the kaleidoscope of Sir David Brewster, the effects being under the control 
of the operator, who is thus able to produce in relief, delicate or simple, 
gorgeous and elaborate patterns, according to his own fancy. 
Dr. Tyndall, in a paper “ On the Absorption and Radiation of Heat by 
Gaseous Matter,” in the “ Philosophical Magazine,” describes what he 
terms “ dynamic radiation and absorption,” or the radiation and ab- 
sorption of heat by gases and vapours without any source of heat external 
to the gaseous body itself. The method he adopts is to admit a minute 
portion of the gas to be examined into the exhausted tube of his apparatus 
for determining the degree of transparency of gases for heat, and then 
allow dry air to enter the tube and mix with it ; the gaseous mixture thus 
increasing in density becomes slightly heated. In the case of boracic ether 
he found that the radiation of an amount of vapour possessing a tension of 
less than a thousand-millionth of an atmosphere was perfectly measurable. 
The absorbent action of perfumes and essential oils for heat was also 
examined ; and, in the instances of spikenard and aniseed, it was found 
to be upwards of 350 times that of dry air. He further examined the 
thermic absorption of electrolytic oxygen, i.e., ordinary oxygen con- 
taining ozone, and found that, in proportion as the size of the electrodes 
