electrical and chemical changes. 41 9 
union of the menstrua ; and no baryta reached the negative, 
and no sulphuric acid the positive pole. 
With muriatic acid and salts of silver the case was the 
same. And when acids and alkalies, forming soluble com- 
pounds, were used in similar experiments, a great length of 
time was required, proportional in some measure to their 
masses, before a particle of acid reached the positive, or of 
alkali the negative pole ; and the result was not destroyed 
till after the intermediate combination had taken place to a 
considerable extent ; proving the phenomena of continued 
decompositions and re-compositions, and showing that the 
electrical and chemical phenomena are of the same order, 
and produced by the same cause. 
In the Bakerian Lecture for 1806, I proposed the electrical 
powers, or the forces required to dis-unite the elements of 
bodies, as a test or measure of the intensity of chemical union. 
By the use of the multiplier it would be now easy to apply 
this test ; and accurate researches on the connexion of what 
may be called the electro-dynamic relations of bodies to their 
combining masses or proportional numbers, will be the first 
step towards fixing chemistry on the permament foundation 
of the mathematical sciences. 
I could enter into some other general views of the pure 
scientific relations of this subject, and its connexion with 
thermo-electricity and the phenomena of cohesion ; but hav- 
ing already taken up so much of the time of the Society, 
I shall defer what I have to say on these subjects to ano- 
ther occasion, and I shall conclude with a few practical 
observations. 
A great variety of experiments made in different parts of 
