before so nearly accomplished as about the time
of the introduction into practical use of Faure's electric storage
batteries; but at the present moment it appears that electric power has
to give way once more to steam power. Mr. Honigmann's invention of the
fireless working of steam engines by means of a solution of hydrate of
soda--NaO HO--in water is not quite two years old, and has in that time
progressed so steadily towards practical success that it is reasonable to
expect its application before long in many cases of locomotion where the
chimney is felt to be a nuisance. The invention is based upon the
discovery that solutions of caustic soda or potash and other solutions in
water, which have high boiling points, liberate heat while absorbing
steam, which heat can be utilized for the production of fresh steam. This
is eminently the case with solutions of caustic soda, which completely
absorb steam until the boiling point is nearly reached, which corresponds
to the degree of dilution. If, therefore, a steam boiler is surrounded by
a vessel containing a solution of hydrate of soda, having a high boiling
point, and if the steam, after having done the work of propelling the
pistons of an engine, is conducted with a reduced pressure and a reduced
temperature into the solution, the latter, absorbing the steam, is
diluted with simultaneous development of heat, which produces fresh steam
in the boiler. This process will be made clearer by referring to the
following table of the boiling points of soda solutions of different
degrees of concentration, and by the description of an experiment
conducted by Professor Riedler with a double cylinder engine and tubular
boiler as shown in Fig. 2:

+---------------------+------------------+----------------------
| | Boiling point in | Steam pressure above
| Solution of soda. | Centigrades. | atmospheric pressure
| | | in atmospheres.
+---------------------+------------------+----------------------
|100 NaO HO + 10 H2O | 256 deg. C. | 40 atm.
| " + 20 " | 220.5 " | 21 "
| " + 30 " | 200 " | 15 "
| " + 40 " | 185.5 " | 10.2 "
| " + 50 " | 174.5 " | 7.7 "
| " + 60 " | 166 " | 6.1 "
| " + 70 " | 159.5 " | 5.1 "
| " + 80 " | 154 "