20 
ANNIVERSARY ADDRESS. 
already been made to the element carbon as familiar in the forms 
of coke and charcoal, and to the fact that when it is made hot in 
a fireplace twelve parts of it will combine with thirty-two {i.e. 
31*92) parts of one of the elements of the air (oxygen), the two 
producing forty-four {i.e. 43*92) parts of carbonic gas. Now such 
is the wonderful character of this combination that the carbon has 
lost its blackness, its hardness, its relative heaviness, and, in short, 
all the properties which enable us to see it and feel it. And such 
is the intensity of the combination that only by the exercise of 
the highest skill and at great cost for apparatus and labour can 
man get back the carbon from the carbonic gas. Such, too, is 
the precision of the combination that the proportion of carbon 
to oxygen in the product is always the same. You may vary 
to some extent the proportions in which, for example, you mix 
flour and water to produce bread, because here you are only calling 
to your aid the mechanical force of adhesion or cohesion ; but if 
you bind things together by the force we are now considering—the 
chemical force—then to produce a given product you are restricted 
in the proportions of constituents, and all the human skill in the 
world cannot vary the proportions. Use more than the stated 
proportion of the one, and the excess will remain behind uncom¬ 
bined ; use more than the fixed proportion of the other, and the 
excess of that also will remain uncombined. Carbon always 
combines in proportions of 12, that is, 12, twice 12, or thrice 12, 
and so on; oxygen in proportions of 16 ; nitrogen, 14; hydrogen, 
1 ; etc. To every element in nature has been given, not by man, 
a combining proportion, which is fixed and invariable, and in this 
proportion each element performs the work it has to do. Not more 
certainly does each of the sixty or seventy notes of a perfectly- 
tuned instrument of music vibrate at a different rate to the others 
but in fitting relationship with them all, than does each of the sixty 
or seventy elements of nature do its work with a power special in 
kind and fixed in quantity but in perfect harmony with the power 
of all the others. Let us sum up respecting the laws governing 
the production, action, and effect of food, and, indeed, governing 
not only the changes which take place within all vegetables and 
animals, but governing all similar changes in nature. Law 1.— 
It has been decreed that the ultimate particles of every one of the 
comparatively few elements which form all the material things 
known to us shall have this marvellous power or force or 
attribute of combination; a power that entirely changes the 
properties of the element or compound on or in which it is exerted. 
Law 2.—The proportions in which the elements so combine are 
