A HARD-WORKING DIET. 3 
words in reference to the starting of trains, or that a 
horse’s “price at starting” would have no reference 
to the cost at which it could be purchased even in a 
“selling stakes ” race. 
If you want to explain to the first man you meet, 
so that it may be of any practical use to him in the 
arrangement of his daily diet, what is the present way 
of regarding the relative use of fish as compared 
with other foods, you must make sure that there is 
a mutual understanding between your hearer and 
yourself about the sense in which you use such words 
” 66 ” 
as “work,” “force,” “burn,” “element,” “ oxidise,” and 
that he knows what you mean when you use such 
words as Carbon, Hydrogen, Oxygen, and Nitrogen. 
Your listener would very probably tell you he 
could not follow you, as he was not familiar with 
your words and terms, and had no idea what they 
meant. You might by degrees find out you had 
to give him very rudimentary information before 
he could follow you at all. 
At the outset, a misunderstanding would very The sense in 
probably occur about the use of the words “element 
and “compound.” The old alchemists meant by 
5, which the 
words 
ment” and 
‘*ele- 
“*compound ” 
“the elements” Earth, Air, Fire and Water, and the 2% "sed. 
term still lingers in our language. It is not uncommon 
to meet with the expression—“the raging of the 
elements” in a description of a thunder-storm, and, in 
an account of a large fire, “the all-devouring element ” 
is pretty sure to be mentioned. The modern chemist, 
however, uses the word “element ” only in contrast to 
“compound.” A compound can be split up into two, 
and, in many cases, three or more essentially different 
materials, as, for example, brass can be split up into 
C 
