RESEARCHES IN ELECTRO-CHEMISTRY. > 41153 
slightest degree of negative polarity by holding these metals 
ever so long against a brush issuing from heated or wetted 
points. 
16. The electrical brush proceeding from heated or moistened 
points does not produce the well-known phosphorus smell. 
The easiest way of depriving the brush of its smell is to cover 
the point of emission with a piece of moistened linen. 
Now in what manner are we to account for the facts above 
stated, and what are the inferences to be drawn from them ? 
As to the smell being developed at the positive electrode 
during the electrolysation of water, we can hardly help drawing, 
from the experiments mentioned in the first section, any other 
conclusion than that it is due to some gaseous substance dis- 
engaged (conjointly with oxygen) from the electrolytic fluid by 
the decomposing power of the current. But what is the nature 
of that substance? Is it elementary or compound? With 
regard to its voltaic bearings, it exhibits the strongest analogy 
to chlorine and bromine; of which bodies I proved, some time 
ago, that they possess, toa high degree, the power of negatively 
polarizing gold and platina. I have also formerly shown, that 
these metals lose again their negative polarity acquired under 
the influence of chlorine and bromine, when plunged into an 
atmosphere of hydrogen; there is, consequently, not the least 
doubt that, as to its electromotive power, the odoriferous prin- 
ciple bears the closest resemblance to chlorine and bromine. 
Now, does not this great analogy between the voltaic properties 
of chlorine, bromine, and our smelling principle, speak in favour 
of the supposition, that these three substances belong to the 
same class of bodies, 7. e. to those which Berzelius called 
‘halogenia’? If we take into further consideration the facts, 
(a) that most metals destroy the peculiar smell, that is, com- 
bine with the odoriferous principle in a direct manner, and even 
at a low temperature; (4) that the said principle is not dis- 
engaged at the positive electrode, unless the latter be composed 
of gold or platina; that is to say, of an eminently electro- 
negative metal ; (c) that the odoriferous body is not eliminated 
by the current, if the electrolytic fluid happens to contain a 
substance having a strong affinity for oxygen, for instance, sul- 
phate of protoxide of iron; and (d) that our peculiar principle 
is always set free at the positive electrode, and never at the 
negative one; I say, if we duly consider all these facts, we can 
hardly help drawing from them the conclusion, that the odori- 
ferous substance is a body very like chlorine or bromine. The 
odoriferous principle, however, may perhaps be nothing but a 
secondary result of the electrolytic action. Such is no doubt 
