149 
BODILY WORK AND WASTE. 
BY FRANCIS T. BOND, M.D., B. A. (Lond.), F.C.S., 
PRINCIPAL OF THE HARTLEY INSTITUTION, SOUTHAMPTON. 
T HERE is no truth which modern science has established 
with greater certainty than that every manifestation of 
physical force involves the metamorphosis of a certain quantity 
of matter; or, to put it in a still simpler form, that every 
exercise of power is made at the cost of a certain consumption 
of material. Whether it be the steam which propels our 
locomotives, or the elastic gases which project our cannon 
balls, the subtle fluid by means of whose vibrations we convey 
our thoughts with the rapidity of lightning from one end of 
the earth to the other, or the still more useful contrivances 
by which we turn night into day, and maintain the genial 
warmth of summer amidst the snows of winter — all these 
exhibitions of force, mechanical, electrical, or thermal, alike 
involve the disintegration, or, in other words, the waste , of 
some form of matter for their production. Without the com- 
bustion of coal or wood there would be no steam for the 
locomotive, no heat for the fireplace; without a similar, but 
more rapid, combustion of gunpowder, or other explosive 
substance, there would be no development of elastic gases in 
the cannon to propel its ponderous missile ; and combustion 
in these, as in all cases, is essentially a process of waste 
in which the active part is played by that most energetic of 
all wasters, the oxygen of the atmosphere. The fluid which 
circulates in the telegraphic wire is developed at the expense 
of the acid and the metals of which the batteries at its extre- 
mities are composed ; and the light which illumines our streets 
and public buildings is generated by the waste (using the term 
in its chemical, not, of course, in its economical sense), in gas 
works, of coal which was produced ages upon ages ago by the 
submergence and partial decomposition of ancient forests. 
Now all these various ways of obtaining power may at first 
sight appear so very simple in their nature that it may seem 
trivial to allude to them. Irrespective, however, of the con- 
