COMPARATIVE POWERS OF MAN, THE HOUSE, ETC. 211 
Albuminous matter . . . . 25‘34 
Fatly matter ..... 8’46 
Sugar and gum . . . . 7*71 
Starch.10*73 
Woody fibre ..... 27'80 
Soluble mineral matters . . . 1*98 
Insoluble mineral matters . . . 6*16 
Water and loss . . . . 11*82 
100-00 
COMPOSITION OF STEEL. 
Steel, according to M. Fremy, is no longer to be con¬ 
sidered a carburet of iron, but nitro-carburetted iron. In 
every instance he has found nitrogen to be a constituent of 
steel. Depending upon the amount of this element re¬ 
tained in combination will be the character of the metal. 
Iron containing only a small portion is converted into 
imperfect steel, but when it is highly nitrogenized, very 
superior steel is formed. 
COMPARATIVE POWERS OF MAN, THE HORSE, &c. 
It is believed that the horse, of all animals, is the best 
adapted for labour. On the authority of Desaguliers and 
Smeaton, his power is considered as equivalent to five men. 
Bossut reckons that of the ass as equal to two men. 
M‘Gauley states that the power of animals is derived from 
the combustion which is carried on in their bodies, and the 
heat derived from this source was originally absorbed from 
the sun’s rays during the growth of those plants which, 
mediately or immediately, form their food; and hence, in 
reality, their force is derived from the sun. 
In like manner he traces up to this source nearly all the 
“ prime movers/ 5 Thus, he says, the power obtained from 
rivers is due to water raised by evaporation, which produces 
its effect while falling back to its original position in the sea. 
The force of the wind, also, is derived from the sun, which 
by rarefying the air in distant regions, causes atmospheric 
currents to be produced. The heat of all fuel is that which 
has been received from the sun during the chemical changes 
which take place in the growth of those plants that con¬ 
stitute not only the forests at present in existence, but those 
belonging to a remote period, and to which our coal-fields 
owe their origin. We need not here speak of the employ¬ 
ment of the steam-engine as a motive power, or of other 
gases or vapours, the effects of heat derived from fuel or by 
other means. 
