SCIENTIFIC SUMMAEY. 
115 
Father Secchi. Father Secchi suggests that beginners could not do better 
than practise on the Bessemer flame before turning their spectroscope on the 
stars. Difficult an instrument to conduct investigations with as the spec- 
troscope undoubtedly is^ the difficulty almost becomes perplexity when the 
student tries to examine stellar spectra. 
A Discovery in Bloiv-pipe Analysis. — Those who use the blow-pipe in 
mineralogical operations should read a paper lately read by Herr Bose before 
the Berlin Academy. In this the German chemist states, that he has foimd 
that the opacity of the glassy bead, which is sometimes observed when the 
specimen has been slowly fused, and which was first pointed out by Berze- 
lius, is due to the formation of crystals in its interior. These crystals are 
usually very small, and are best observed with the assistance of the micro- 
scope 5 but they are occasionally very large, and may be seen with the naked 
eye. Herr Bose has described to the Berlin Academy a practical application 
of his discovery, by which he was able easily to produce the three allotropic 
forms of titanic acid. — Vide L’lnstitvt, Oct. 30. 
Experiments in Actinometry, recently tried on Mont Blanc by the Society 
of Geneva, and reported to the French Academy, give results opposed to the 
conclusions formed by Prof. Forbes from his experiments on the Faulhorn. 
The Spectroscope in Toxicology. — Mr. H. C. Sorby, F.B.S., who continues 
his investigations of animal and vegetable substances with the spectroscope, 
has been recently studying the spectra produced by the colouring-matters of 
such substances as belladonna, &c. At a late meeting of the Philosophical 
Society of Sheffield he read a paper on the application of the spectroscope 
to medical jurisprudence. In this he showed how great are the difficulties 
which meet the toxicologist in his efforts to prove a case of poisoning by 
belladonna. When the seeds are present, their form offers a fair guarantee, but 
they are often absent, and then proof of poisoning becomes a serious question. 
Mr. Sorby showed that the difficulty was obviated by the use of the micro- 
spectroscope. The spectrum of the juice of belladonna is very distinct, 
especially when the colouring-matter has been added to solution of carbonate 
of soda. There are one or two other vegetable juices whose spectra are 
somewhat similar, but these could be at once distinguished by an appeal to 
the general history of the case. A small fraction of a single berry is 
sufficient to produce the characteristic spectrum-bands of belladonna. 
Magellan's Barometer. — In reply to M. Badau’s assertion that the principle 
of the static barometer was well known to both Magellan and Maguire, 
Signor Secchi has published a contradicting note, in which he states : — 
1. Neither Magellan nor Maguire understood the true principle of the action 
of the static barometer ; 2. They suggested apparatus quite impossible to 
construct, and which they failed to construct themselves ; 3. The impossi- 
bility of construction explains why this instrument fell into oblivion. — ■ 
Comptes Rendus, tom. Ixv., No. 11. 
The Crystallography of Potash Salts, and also of Oxalate of Ammonia, have 
been investigated by M. A. Brio, of Charkoar, who alleges that the tartrate 
X)f potash and oxalate of ammonia both belong to the rhombic system. 
A Traveller's Barometer . — Senor F. de Bruno has constructed an instru- 
ment which is intended to stand the rough test of travel. It is made of iron, 
and acts perfectly in all positions. It is not liable to injury from shocks. 
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