NATURAL PHILOSOPHY. 107 



generally considered that the sun's light is essential to its develop- 

 ment. From M. Mangon's experiments, however, it appears that 

 the electric light is equally capable of inducing its formation. 



The electricity was produced by an electro-magnetic machine 

 worked with a steam-engine. The light was obtained from a lamp 

 with charcoal points. On the morning of the 30th July, severed 

 flower-pots, each containing four grains of rye, sown respectively on 

 the 24th, 26th, 27th, and 28th of July, were placed in a large space, 

 perfectly secluded from external light, the pots standing about one 

 metre from the electric lamp, and half, a millimetre below the point 

 of light. By the 2d of August all the plants had developed as well 

 as if they had been in the open air, and all exhibited their natural 

 green color. On the third of August the experiment was brought 

 to an end. It is scarcely necessary to add that some corresponding 

 seeds grown in darkness for the same period were perfectly yellow. 



It follows from the above, that the electric light, like sunlight, is 

 capable of causing the development of the green parts of plants. It 

 has been previously shown that the light resulting from very intense 

 combustion, such as results from pyrotechnic compositions, for in- 

 stance, is capable of producing the same effect. 



ELECTRICAL MEMORANDA. 



In September, 1861, the beautiful experiment was made of illumi- 

 nating the famous Falls of Schaffliauseii on the Rhine, thirty yards in 

 height, by means of five electric lights. The effect is said to have been 

 marvellous, especially when viewed through colored glasses ; the waves 

 of the river resembled a sea of fire. 



Electric Light applied to Surgery. One of the greatest obstacles 

 to the success of a surgical operation is the scanty and imperfect light 

 which, in some cases, is the surgeon's only guide, and is fraught with 

 danger to the patient. Thus the extirpation of a naso-pharyngian 

 polypus is performed in almost absolute darkness, it being impossible 

 to bring a common light near enough to the patient without scorch- 

 ing him. The problem, therefore, of finding a light which might be 

 introduced into a cavity with impunity, remained still to be solved ; 

 and, from a communication sent in some months since to the Academy 

 of Sciences, by MM. Th. Doumoncel, Foussagrives, and Ruhmkorff, 

 it would appear that this desirable object has at length been attained. 

 Dr. Foussasrives, having lono; entertained the idea that the electric 



^3 CD O 



light might be advantageously applied to the purpose, communicated 

 his views to M. Doumoncel, a distinguished electrician, who, calling to 

 mind the effects of electricity in vacuo, as exemplified in Giessler's 

 tubes, which, although traversed by the electric light, reveal no in- 

 crease of temperature, conceived the following plan for turning this 

 circumstance to account in surgical cases of the nature alluded to. 

 A glass tube, having a very smaU bore, is bent into the form of a 

 helix or screw (the smaller the bore the greater the brilliancy of the 

 light) : by this means a kind of luminous cylinder is formed, which 

 is sufficiently small to be conveniently introduced into a narrow cavity 

 Thus the first part of the problem was solved ; but the color of the 

 light was yet to be determined, since this depends on the nature of 



