MICHAEL FARADAY i93 



perature of 50° ; a part of the chlorine volatilised, and cooled the tube 

 so much as to condense the atmospheric vapour on it as ice. 



A tube having the water at one end and the chlorine at the other 

 was weighed, and then cut in two ; the chlorine immediately flew off, 

 and the loss being ascertained was found to be 1.6 grains: the water 

 left was examined and found to contain some chlorine : its weight was 

 ascertained to be 5.4 grains. These proportions, however, must not 

 be considered as indicative of the true composition of hydrate of 

 chlorine ; for, from the mildness of the weather during the time when 

 these experiments were made, it was impossible to collect the crystals 

 of hydrate, press, and transfer them, without losing much chlorine; 

 and it is also impossible to separate the chlorine and water in the tube 

 perfectly, or keep them separate, as the atmosphere within will com- 

 bine with the water, and gradually reform the hydrate. 



Before cutting the tube, another tube had been prepared exactly 

 like it in form and size, and a portion of water introduced into it, as 

 near as the eye could judge, of the same bulk as the fluid chlorine : this 

 water was found to weigh 1.2 grains; a result, which, if it may be 

 trusted, would give the specific gravity of fluid chlorine as 1.33; and 

 from its appearance in, and on water, this cannot be far wrong. 



ELECTRICITY FROM MAGNETISM 



Read November 24, 18^1. 



1. The power which electricity of tension possesses of causing an 

 opposite electrical state in its vicinity has been expressed by the gen- 

 eral term Induction ; which, as it has been received into scientific 

 language, may also, with propriety, be used in the same general sense 

 to express the power which electrical currents may possess of inducing 

 any particular state upon matter in their immediate neighborhood, 

 otherwise indififerent. It is with this meaning that I purpose using it 

 in the present paper. 



2. Certain effects of the induction of electrical currents have al- 

 ready been recognized and described: as those of magnetization; 

 Ampere's experiments of bringing a copper disc near to a flat spiral ; 

 his repetition with electro-magnets of Arago's extraordinary experi- 

 ments, and perhaps a few others. Still it appeared unlikely that these 



