116 DR. FARADAY'S EXPERIMENTAL RESEARCHES IN ELECTRICITV. 



feel no hesitation in believing that the latter must submit to them also. Such being 

 the case, I can have no doubt that, assuming hydrogen as 1, and dismissing small 

 fractions for the simplicity of expression, the equivalent number or atomic weight of 

 oxygen is 8, of chlorine 36, of bromine 78*4, of lead 103-5, of tin 59, &c., notwith- 

 standing that a very high authority doubles several of these numbers. 



4 13. On the absolute quantity of Electricity associated with the particles or atoms of 



Matter. 



852. The theory of definite electrolytical or electro-chemical action appears to me 

 to touch immediately upon the absolute quantity of electricity or electric power be- 

 longing to different bodies. It is impossible, perhaps, to speak on this point without 

 committing oneself beyond what present facts will sustain ; and yet it is equally im- 

 possible, and perhaps would be impohtic, not to reason upon the subject. Although we 

 know nothing of what an atom is, yet we cannot resist forming some idea of a small 

 particle, which represents it to the mind ; and though we are in equal, if not greater, 

 ignorance of electricity, so as to be unable to say whether it is a particular matter or 

 matters, or mere motion of ordinary matter, or some third kind of power or agent, yet 

 there is an immensity of facts which justify us in believing that the atoms of matter 

 are in someway endowed or associated with electrical powers, to which they owe their 

 most striking qualities, and amongst them their mutual chemical affinity. As soon 

 as we perceive, through the teaching of Dalton, that chemical powers are, however 

 varied the circumstances in which they are exerted, definite for each body, we learn 

 to estimate the relative degree of force which resides in such bodies : and when upon 

 that knowledge comes the fact, that the electricity, which we appear to be capa- 

 ble of loosening from its habitation for a while, and conveying from place to place, 

 whilst it retains its chemical force, can be measured out, and, being so measured, is 

 found to be as definite in its action as any of those portions which, remaining associated 

 with the particles of matter, give them their chemical relation ; we seem to have found 

 the link which connects the proportion of that we have evolved to the proportion of 

 that belonging to the particles in their natural state. 



853. Now it is wonderful to observe how small a quantity of a compound body is 

 decomposed by a certain portion of electricity. Let us, for instance, consider this and 

 a few other points in relation to water. One grain of water acidulated to facilitate 

 conduction, will require an electric current to be continued for three minutes and three 

 quarters of time to effect its decomposition, which current must be powerful enough 

 to retain a platina wire -^^ of an inch in thickness*, red hot, in the air during the 

 whole time ; and if interrupted anywhere by charcoal points, will produce a very 



* I have not stated the length of wire used, because I find by experiment, as would be expected in theor}', 

 that it is indiiFerent. The same quantity of electricity which, passed in a given time, can heat an inch of platina 

 wire of a certain diameter red hot, can also heat a hundred, a thousand, or any length of the same wire to the 

 same degree, provided the cooling circumstances are the same for every part in both cases. This I have proved 

 by the volta- electrometer. I found that whether half an inch or eight inches were retained at one constant 



