AT THE MOMENT OF CHEMICAL CHANGE. 767 
inents of the system on the other, and this, during’ the action and under the influence 
of the chlorine, it may truly be. 
If it be true that in the preceding experiments this polar division of the element 
takes place, (a division, at any rate, in many points analogous to the decomposition 
of the compound body when no elemental substance is isolated, but the particles are 
transferred from one system to another,) it cannot but be, that in the formation of 
the element the correlative fact is to be observed, and that the element itself is made 
by the synthesis of polar particles. This is indicated by theory, and although the 
more usual mode of forming these elemental bodies is not such as to bring to light 
the true nature of this synthesis, there are other, although as yet rarer, instances of 
the formation of these bodies, which not only are not opposed to this view, but 
prove it. 
1. When an acid is added to a perfectly pure solution of an alkaline iodide, such 
as may readily be procured by precipitating any iodate it contains by baryta water 
and filtering, the solution remains perfectly clear. Neither, when an acid is added 
to a pure solution of iodate of potash, is there any alteration, but on mixing these 
solutions an abundant precipitate of iodine is formed. It is said that the iodate and 
iodide of zinc, without acid, undergo a similar decomposition. It is very plain that 
these changes are simple cases of what is called double decomposition. The hydri- 
odic and iodic acids decompose one another, and it is my opinion that in the change 
lOgH+SHI^GHO+el, 
whatever be that combining relation which subsists between the oxygen and hydrogen, 
that same relation must also be between the particles of the iodine itself. What is 
commonly called the affinity of hydrogen for oxygen is not sufficient to account for 
this change, for hydrogen alone will not decompose the iodic acid, unless it be in the 
nascent condition. When hydrochloric acid is the decomposing body, chloride of 
iodine is formed, when hydriodic acid, the iodine itself. Are we not to admit that 
these two substances are formed according to the same law ? To this synthesis of 
the iodine, the division of the element whieh takes place at the formation of the 
hydriodic and iodic acids, is the correlative fact, to explain which we must assume 
the same polar difference between its particles (see page 765). 
2. In the course of his researches on the hypophosphites, Wurz discovered a very 
singular substance, the hydruret of copper*. This substance is formed by the action 
of hypophosphorous acid upon copper salts. It readily decomposes, so that it is not 
easy to determine its constitution, but his analyses very closely corresponded with 
the formula CU 2 IT. That this is truly the formula of the substance, may be inferred 
with yet more certainty than from the analyses, from the following curious reaction. 
* Berzelius attempted to throw some doubt upon the existence of this body, but the correctness of the 
facts, as stated by Wurz, is guaranteed, not only by the well-known skill and ability of this chemist, but also 
b}'^ the fact that Poggendorff had succeeded in procuring a hydruret of copper by the electrolysis of the 
sulphate of this metal. 
