660 THE EVOLUTION OF COMMERCE. 
other. Here will be the great banking and commercial houses of the 
world, the center of business, wealth, and population. 
The end is not yet. Inventions are increasing in a geometric rather 
than an arithmetic progression. The limit of steam power has not 
been reached, for with a high temperature in a steam boiler the addi- 
tion of a few pounds of coal increases the steam power so greatly that 
we are unable either to control or to use it. / 
Electricity has just begun to offer new opportunities to commerce. 
We are no longer compelled to carry our factories to the water power, 
for by the electric wire the power may be brought to the house of the 
operative, and we may again see the private workman supersede the 
factory operative. A few cars and small vessels are moved by elec- 
tricity, the forerunner of greater things. We know little of this new 
agency, but its future growth must be more rapid and more wonderful 
than that of steam. 
The Secretary of the Smithsonian Institution (Mr. Langley) tells us 
that ‘before the incoming of the twentieth century aérial navigation 
will be an established fact.” 
“The deeper the insight we obtain into the mysterious workings of 
nature’s forces,” says Siemens, “the more we are convinced that we are 
still standing in the vestibule of science; that an unexplored world still 
lies before us; and however much we may discover, we know not whether 
mankind will ever arrive at a full knowledge of nature.” 
