hese
cars a connection is made by a flexible India rubber pipe to one of ten
stand pipes which project 1 ft. above the ground line. Parallel with the
rails is laid a main pipe, with which the ten stand pipes are all
connected, thus forming one general suction main. About the middle of the
length of the main, which is laid underground and covered with sawdust or
other non-conducting material, is fixed a Blake steam pump. As soon as all
the ten connections are made with the cistern cars, the pump is set to
work, and in about one hour the whole of the cars are discharged into the
main reservoir, the time depending of course upon the capacity of the
pump. All the pipes used are of malleable iron, lap-welded, and of 5 in.
internal diameter, having screwed coupling muffs for making the
connections. At each engine shed, in addition to the main storage
reservoir, there is a smaller distributing tank, which is erected at a
sufficient height to supply the tenders, and very much resembles the
ordinary water tanks. These distributing tanks are circular, about 81/2 ft.
diameter and 6 ft. high, and of 1/4 in. plates; their inside mean area is
calculated exactly, and a scale graduated in inches stands in the middle
of the tank; a glass with scale is used outside in summer time. Each inch
in height on the scale is converted into cubic feet, and then by means of
a table is converted into Russian poods, according to the specific gravity
at various temperatures. As it would be superfluous to graduate the table
for each separate degree of temperature, the columns in the table show the
weights for every 8 degrees Reaumur, which is quite sufficient: namely,
from 24 deg. to 17 deg., from 16 deg. to 9 deg., and so on, down to -24
deg.; the equivalent Fahrenheit range being from 86 deg. down to -22 deg.
Suppose the filling of a tender tank draws off a height of 27 in. from the
distributing tank, at a temperature of say -20 deg. R., these figures are
shown by the table to correspond with 200.61 poods = 7,245 lb., or 3.23
tons, of petroleum. This arrangement does very well in practice; both the
quantity and the temperature are entered on the driver's fuel bill at the
time of his taking in his supply.

_Engines._--The engines used in the trials were built by Borsig, of
Berlin, Schneider, of Creusot, and the Russian Mechanical and Mining
Company, of St. Petersburg. Their main dimensions and weights were about
the same, as follows, all of them having