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POPULAR SCIENCE REVIEW. 
electric action of the prismatic rays. He allowed the solar rays to play 
upon a delicate Nobili’s galvanometer, and observed that very considerable 
deflections took place, in some instances amounting to 90°. He ascertained 
that these deflections of the needles were not the result of any change 
of temperature, and that they were not due to currents of air ; hence, he 
fairly concluded, that they were the immediate result of the action of 
the rays themselves. When in the shade the needles remained quite 
immovable ; but the moment that the rays were allowed to play on them, 
deflections took place, which were invariably greater for the violet than for 
the other colours. 
The Numerical Nomenclature of Spectral Lines. — This is the subject of a 
note in a late number of the Chemical News , by Mr. Emerson Reynolds, of 
Dublin. There is a great want of uniformity in the modes adopted for the 
subdivision of the spectrum. The results obtained in most instances are 
not practically available for easy reference. This the writer attributes to 
the circumstances that no two prisms have identical angular values, and 
no two telescopes are of exactly the same magnifying power. He proposes 
that two clearly defined lines be taken (like the zero and boiling-point of 
a centigrade thermometer), and that the interval between them be divided 
into a hundred equal parts ; in this way, at all events, a constant relative 
measure would be arrived at. He proposes to make Alpha in the lithium 
the zero, and Delta in the strontium, the hundredth division of the new 
scale. 
The Use of Prisms of Flint-Class and Bisulphide of Carbon for Spectral 
Analysis . — From the investigations of Sigmund Merz, published in 
“ Poggendorf’s Annalen,” it would seem that Professor Rood’s new bi- 
sulphide of carbon prism is a much more accurate and valuable instrument 
than was at first supposed, and also one which on account of its com- 
parative cheapness deserves to be employed. In 1862, Professor Rood 
mentioned (in a letter to Professor Silliman) the discovery of two new 
lines in the interior of the line D, which, added to that before described by 
Kirchhoff, made three fine lines. The instrument he used was composed 
of three bisulphide of carbon prisms of 60°, with a flint-glass prism of 46°, 
the sum of the refracting angles being 125°, and the telescopes employed 
being the common French instruments. On the other hand, Merz states 
that with a series of glass prisms, the sum of whose refracting angles was 
270°, he only discovered the second line in the interior of D, and failed to 
observe the third, which had been detected by Professor Rood. — Vide 
“ American Journal of Science and Art,” XXXV. 856. 
The Electric SparJc. — M. Daniel has been instituting a number of ex- 
periments on the spectra produced by the electric spark when generated 
indifferent media, liquid and gaseous. The liquids employed were : — 
sulphuric ether,' absolute alcohol, sulphide of carbon, essence of turpentine, 
benzine, aniline, naphtha, chloroform, protochloride of phosphorus, distilled 
water, &c. The machine employed was a middle-sized one of Ruhmkorff ’s ; 
balls of copper, zinc, lead, tin, cadmium, &c., were used as electrodes, and, 
except in the case of liquids offering a feeble resistance, short sparks of 
about two or three millimetres were experimented on. The spark is 
generally more vivid than in the air, and its colour varies with the medium 
