430 Chronicles of Science. [July, 



bands are indicated by * printed over their centre. In Mr. Sorby's 

 paper examples are given which show how simple or more compli- 

 cated spectra may readily be printed and compared. For instance, 

 the spectrum of normal chlorophyll dissolved in alcohol (deep 

 green), is represented bv : — 



* " I 



t — «t — ■» *» 6f-~7£- 



and the spectrum of the same body, as decomposed by acids, as 



found in some leaves (olive green), by : — 



1 — 2i 2£---3§ 4i...5i---5f ... 6§ -*-- 7| Bi.~ 9§— 



The instruments and methods were exhibited and explained by 

 Mr. Sorby and Mr. Browning at the last soiree of the Boyal 

 Society, where they excited the greatest interest. 



The Bev. Father Secchi has continued his researches on the 

 spectra of several classes of stars. He explains by the differences 

 of temperature, or by the effect of absorption, the variation in inten- 

 sity of certain Hues — the hydrogen line F, for example. 



The electric light has recently been fitted up on board the 

 1 Prince Jerome,' the yacht of H.I.H. the Prince Xapoleon ; and 

 several interesting experiments are to be tried with it. It is not 

 proposed to illuminate the vessel itself, but, on the contrary, to light 

 up other objects, such as a coast or a vessel for the object of attack 

 or defence ; ships at full speed or in station can thus be kept free 

 of all danger of collision, and, in action, the object to be hit can be 

 illuminated. The lamp is that known as Duboscq's, which has the 

 advantage of not only having a regular movement when in a ver- 

 tical position, but also burning with the same precision inclined at 

 any angle, so as to be independent of the pitching or rolling of the 

 vessel at sea. An apparatus is placed behind the lamp, which, 

 hiding the light from the deck of the vessel, projects it in parallel 

 rays on a given spot. Once proved to be useful on board a vessel, 

 the electric light will soon be considered a necessary adjunct to the 

 marine and transport service. The employment of the same light 

 for railways, in the stations and approaches, tunnels, curves, &c, 

 his been actively experimented on in France for some time past. 



The question has again been raised of substituting the magneto- 

 electric current for that of the battery in electrotyping. electro- 

 plating, and. gilding. The magneto-electric machine of Mr. AVilde 

 has been employed in the well-known establishment of Messrs. Elk- 

 ington, and in Paris M. Christophe and M. Bouillet have resolved to 

 make use of electricity engendered mechanically. They made a first 

 trial at the works of the Alliance Company, and they have ordered 

 two machines of four discs. In the establishment of Iff. Lenoir, 88, 

 Bue Popincourt, a machine of this kind has been fitted up, which 



