316 Dr. Faraday's Researches in Electricity. 



tion of matter, that we ought not too hastily to assume that 

 the substances which, in the solid and liquid state, possess 

 properties even general in character, always carry these into 

 their gaseous condition. 



2238. Rock-salt, fluor-spar, and, I think, alum, affect the 

 ray of light; the other crystals experimented with did not; 

 these are equiaxed and singly refracting, the others are un- 

 equiaxed and doubly refracting. Perhaps these instances, 

 with that of the rotation of quartz, may even now indicate a 

 relation between magnetism, electricity, and the crystallizing 

 forces of matter. 



2239. All bodies are affected by helices as by magnets, 

 and according to laws which show that the causes of the ac- 

 tion are identical as well as the effects. This result supplies 

 another fine proof in favour of the identity of helices and mag- 

 nets, according to the views of Ampere. 



2240. The theory of static induction which I formerly ven- 

 tured to set forth (1161, &c), and which depends upon the 

 action of the contiguous particles of the dielectric intervening 

 between the inductric and the inducteous bodies, led me to 

 expect that the same kind of dependence upon the intervening 

 particles would be found to exist in magnetic action ; and 

 I published certain experiments and considerations on this 

 point seven years ago (1709 — 1736). I could not then dis- 

 cover any peculiar condition of the intervening substance or 

 diamagnetic ; but now that I have been able to make out such 

 a state, which is not only a state of tension (2227), but de- 

 pendent entirely upon the magnetic lines which pass through 

 the substance, I am more than ever encouraged to believe 

 that the view then advanced is correct. 



2241. Although the magnetic and electric forces appear 

 to exert no power on the ordinary or on the depolarized ray 

 of light, we can hardly doubt but that they have some special 

 influence, which probably will soon be made apparent by ex- 

 periment. Neither can it be supposed otherwise than that 

 the same kind of action should take place on the other forms 

 of radiant agents as heat and chemical force. 



2242. This mode of magnetic and electric action, and the 

 phamomena presented by it, will, I hope, greatly assist here- 

 after in the investigation of the nature of transparent bodies, 

 of light, of magnets, and their action one on another, or on 

 magnetic substances. I am at this time engaged in investi- 

 gating the new magnetic condition, and shall shortly send a 

 further account of it to the Royal Society. What the possi- 

 ble effect of the force may be in the earth as a whole, or in 

 magnets, or in relation to the sun, and what may be the best 



