220 
DR. GLADSTONE ON CIRCUMSTANCES MODIFYING 
During the controversy that ensued after the publication of Berthollet’s treatise, 
many reactions were brought forward to prove the falsity of his views. Most of these 
were directed against certain positions of the French philosopher which were certainly 
untenable, while others were founded on a misapprehension of the question at issue. 
Those which appear the most formidable against the conclusions arrived at in this 
paper are, that boracic acid, or carbonic acid, or hydrosulphuric acid, are incapable 
of decomposing in the least degree sulphate of potash, or any analogous salt ; and that 
chloride of sodium is not affected at all by iodine. The proof of these statements 
rests in each instance upon the testimony of blue litmus paper. In the first case the 
vegetable colour is not reddened ; which is supposed to prove that no sulphuric acid 
has been liberated ; yet if any had been set free there must have been formed at the 
same instant an equivalent amount of borate, or carbonate, or hydrosulphate of pot- 
ash, each of which has an alkaline reaction, and would have restored the blue, or 
rather prevented the litmus from reddening. So in the case of the common salt and 
iodine (where by the way only one base is concerned), the chlorine, supposing it libe- 
rated, would not have bleached the litmus, but would have combined at the moment 
of its separation with some of the iodine present to form the terchloride of iodine 
which has a neutral reaction. That very little decomposition does take place in 
these instances I have no doubt, but that there is actually none is not proved. 
There is however one difficulty not so easily overcome. Water is a binary com- 
pound, and it might be expected that on mixing a hydrated acid and base, or on dis- 
solving in water a salt, such as nitrate of potash, or nitrate of ammonia, a certain 
amount of both the acid and the base would remain in combination merely with 
water. That it is not so, is proved by the fact that solutions of the salts just named 
do not give up any portion of their volatile base or acid, even on boiling. Has a 
limit to the action of the general law been here arrived at? Is water an exception 
standing by itself? Or is there not an assumption in supposing that water is not an 
integral part of the constitution of every salt when in a state of aqueous solution ? 
To these queries I do not feel myself in a position as yet to make a reply. 
Conclusions. 
The general conclusions arrived at in this paper may be summed up as follows: — 
I. Where two or more binary compounds are mixed under such circumstances 
that all the resulting bodies are free to act and react, each electro-positive element 
arranges itself in combination with each electro-negative element in certain con- 
stant proportions. 
II. These proportions are independent of the manner in which the different elements 
were originally condiined. 
III. These proportions are not merely the resultant of the various strengths of 
affinity of the several substances for one another, but are dependent also on the mass 
of each of the substances in the mixture. 
