422 Scientific Intelligence. 
give uniformly to the steam the tension desired. The usual pressure 
in the boiler is 5 to 10 atmospheres.. 
In bringing the generator into action, it is heated dry for some min- 
utes; then by means of a hand pump, a few glasses of water are 
thrown into the boiler, the steam-guage being put in connection, and 25 
minutes afterward, the engine is brought into action which feeds thence 
the boiler. 
In an experiment continued for 9 hours, 351 kilograms of water 
were evaporated, whose initial temperature was 39° C, The coal con- 
sumed was 81 kilograms; pressure produced, 10 atmospheres. This 
pressure supposes a temperature of about 181° C., and since, accord- 
ing to Baudrimont, iron possesses its greatest tenacity at near 200° C., 
invention is ex . He recognizes the following. 
1. The decomposition of water, by the red-hot metal. 
2. Excess or deficiency in the supply for the boiler. As to the first, 
if it takes place, there is actually no increase in the volume of the vapor} 
6 volumes of steam (3120), plus 2 of iron (Fe2), give 6H-+Fe?0*. 
As to the second, it is apparent that the vapor will decrease rapidly as 
the supply is suspended, and the danger will thus be averted. But it 
may be feared that the bottom of the boiler being no longer supplied 
with water will redden strongly ; and that when water is admitted, this 
yesult 
The 
fear of such a catastrophe is dissipated on inspecting figure 1, where it 1s 
: Engine of M. Andrand, called Electro-caloric.—In 1844, after rae 
eral Eeyeratory trials, M. Andrand put in action on the railroad pie 
Paris to Versailles an air-locomotive, in the presence of a commissio® 
‘ semblance, It 
by government. though with some points of re 
= sihoug P gooretes™ 
was hot recisely a caloric engine like that of Ericsson, agai er 
_ -ndrand enters no claim of priority. ‘The locomotive acted ~ ws 
air at first compressed in a heater and then dilated by the heat. T 
acted at high pressure and the generator consisted of a worm plunged 
in a fire for the purpose ; on passing through this spiral tube, the 2 
was dilated, then on reaching the motor cylinders it underwent § 
tional dilatation, for the concave bottom of the cylinders were fur 
with plates of cast iron, which were at a whi 
