Electric Illumination, — Atmospheric Electricity. 411 



by the word metalejjsy^ an expression wliich has been attributed to 

 Berzelius, 



But the theory of substitutions required tor its completJon a correct 

 tno\Y]edge of the part in tlie changes played by chlorine. It will be re- 

 membered that the idea of Laurent that ''m the bodies obtained by sub- 

 stitution, chlorine not only takes the place of hydrogen, but acts the 

 same part with it," met with general denunciation. It was followed by 

 the bitter criticisms of Berzelius, Liehig, and Wohler, and a declaration 

 by Dumas disclaiming all participation in the view, which he called au 

 "exageration (nitree de sa theorie," 



For some time Laurent was alone: but after a %yhile In's time of tri- 

 umph came. The theory was then attributed AvhoUy to him. But the 

 note pubh'shed by Dumas in Xh^d Annales de Chimie et de PI»ysique, dis- 

 pels all doubts and leads to justice being rendered to each of the two 

 chemists, — to Dumas who opened the way, and to Laurent who estab- 

 lished the theory and rendered it of practicable value. 



Electric illuminatiorK' -We have spoken of the experiments in electric 

 illumination made at Lyons by Lacassaigne and Tliicrs, They have con- 

 tinued their trials with great success, and through the month of March 

 hghted one of the principal streets of Lyons, between the hours of seven 

 to eleven. Two pieces of apparatus set up at the extremities of the street 

 upon a frame crossing between the roofe of the opposite houses, sent 

 their beams down the middle of the street. The gas was not lit; al! the 

 illumination was obtained from the battery. Tlie Rue Imperial is about 

 660 yards long, and is lighted with more than forty jets of gas; and yet, 

 the gas light was fully replaced by the electric light. Something still 

 remains to be done. It is important tliat the light should come from a 

 much greater height, that it may be more diffused, and less blinding and 

 fatiguing to the sight. 



Atmospheric eleclricity. Theory of thunder, — Among the theories of 

 thunder, the recent one of M. Jobard, Director of the Museum of Indus- 

 try of Brussels, should be counted ; it may be called the chemical theory. 

 According to it, thunder is nothing but the detonation of a detonating 

 luixture of hydrogen gas, more or less carburetted, along witli atrnos* 

 pheric air. The gas comes from decomposing organic matters and goea 

 up in ''pluies ascendants." Moreover he assumes that the same gas sus- 

 tains the clouds, the water vesicles being filled with it. M, Jobard's fer* 

 tile mind is so pressed with making tlieories for every thing that it does 

 not give time for verifying them. He gets rid of the hydrogen again by 

 supposing it to form water; and also ammonia with the nitrbyen of the 

 air. 



-^ew anesthetic agents. — Besides other agents proposed for replat^ing 

 ether and chloroform in anesthesis, amylene (C^^II*^) has been proposed. 

 It was discovered in 1844 by M. Balard, Professor in the Fatmlty of 

 Sciences at Paris. It was fii^t aj)plied by Mr. John Snow, and for a 

 while prod uc-ed considerable sensation in the medical world. It may be 

 questioned however whether it is better than aldehyde, artificial oil of 

 naphtha, Dutch liquid, and other bodies of the class of ethm or hydro- 

 carbons, which have been set down, on examination, as inferior to chloro- 

 form. However, according to the experiments at Paris of Dr. Geraldes, 

 the amylenic anesthesis is more easily obtained than that by means of 



