Oct. 12, 1888.] 



SCIENTIFIC NEWS. 



385 



GAS-BURNER ON THE LEBRUN 

 SYSTEM. 



THE apparatus which we (La Nature) are about to 

 figure and describe is based on the same prin- 

 ciples as the Siemens burner, the Wenham lamp, etc., 

 though its mode of construction is different. Our figure 

 shows the external aspect of the lamp and the principal 

 internal arrangements. It consists of a glass globe, at 

 the lower part of which enters the copper tube (D) con- 

 veying the gas. Above this burner is placed a cylindri- 

 cal cover (C), closed on all sides, but having its lower 

 part (B) pierced with a multitude of small holes, whilst 

 the upper part communicates with the external air by the 

 pipes (A). 



The upper part of the globe is closed by a metallic 

 crown ; a disc of asbestos interposed between this 

 crown and the globe forms an air-tight joint, so that there 

 is no communication with the external atmosphere ex- 

 cept by a glass chimney traversing the crown. 



of the question. Of course the three great objections 

 against gas — the heat, the danger of fire, and the pro- 

 duction of sulphurous acid — remain as in the case of 

 ordinary gas-burners. 



ON THE PART PLAYED BY SYMBIOSIS 

 IN CERTAIN LUMINOUS MARINE 

 ANIMALS. 



THE following communication has been made to the 

 Academy of Sciences of Paris by M. Raphael Du- 

 bois : — " In former communications I have been led to 

 admit that the fundamental reaction necessary for the 

 production of light in animals belonged to the class 

 which take place under the action of ferments. In the 

 session of May 12 th of the present year, I made known 

 to the Society of Biology the existence, in a normal state, 

 in the walls of the syphon of Pholas daclylus of micro- 

 organisms {Bacillus pholas), which give a fine light when 



Gas Burner on the Lebrun System. 



The lower part of the globe is formed by a trap, which 

 is opened only at the moment of lighting the gas. 



The working of the system is easily understood. 

 When the gas is lighted at D and the trap closed the 

 air in the globe is heated and escapes by the chimney. 

 There is thus produced a draught, which forces the ex- 

 ternal air to arrive by the pipes (A) into the cylindrical 

 cover (C), and to escape by the small holes made in B. 

 Hence it is intimately mixed with the crown of flame of 

 the burner (D), and the combustion is as complete as 

 possible. 



The light is very white and very steady, the gas is 

 almost entirely utilised, and for an equal illumination 

 there is a decided economy in the consumption. This 

 burner is constructed of three different sizes, having an 

 illuminating power of 4, 9, and 16 carcels respectively. 

 The apparatus has a screw thread, so that it may be 

 placed in gaseliers, candelabra, etc., instead of the old 

 burners. 



It is recommended, e.g., for use in provincial theatres 

 where the expense of an electric light installation is out 



cultivated in a decoction prepared with the phosphores- 

 cent tissues of the living animal. These tissues contain 

 the substance which I have provisionally named 

 luciferine, upon which the ferment acts. The reaction 

 requires for the production of light a suitable medium ; 

 it must be rendered saline and alkaline in certain fixed 

 proportions. During life the liquid is furnished by the 

 animal, which modifies it as the case requires. It is not 

 the same in the mollusc at rest, which does not shine, 

 as in one which is excitad and emits En abundant 

 quantity of the phosphorescent liquid. 



We have, therefore, in Pholas daclylus a new case of 

 symbiosis, most interesting from several points of view. 



I found, in June last, in the mucus secreted by the 

 mantle of Pelagia noctiluca, a micro-organism which may 

 be extinguished or rekindled at will by varying the con- 

 ditions of the medium. 



During its changes of physiological activity the Bacillus 

 pholas possesses a great morphological fixity. It is not 

 the same with the new organism of the pelagia (Bac- 

 terium pelagia). If cultivated in gelatine it rapidly exca- 



