at might be surmounted by using at the
beginning of the operation a very small auxiliary boiler. The main
furnace would then be fired by means of say a wad of cotton. But, in
current practice, if a grate and fire be retained, the firing will
perhaps be simpler.

With but one apparatus, the pressure in the Flamboyante's boiler rose
in a few minutes from 6 to 25 pounds, and about a quarter of an hour
after leaving the wharf the apparatus had been so regulated that there
was no sign of smoke. This property of the Dietrich burner proceeds
naturally from the use of a jet of steam to carry along the petroleum
and air necessary for combustion. It is, in fact, an Orvis smoke
consumer transformed, and applied in a special way.

It must be added that the regulating requires a certain amount of
practice and even a certain amount of time at every change in the
boat's running. So it is well to use two, and even three, apparatus,
of a size adapted to that of the boiler. The regulation of the furnace
temperature is then effected by extinguishing one or two, or even
three, of the apparatus, according as it is desired to slow up more or
less or to come to a standstill.

The oil used by Mr. De Dosme on his yacht comes from Comaille, near
Antun. The price of it is quite low, and, seeing the feeble
consumption (from 33 to 45 lb. for the yacht's boiler), it competes
advantageously with the coal that Mr. De Dosme was formerly obliged to
use.--_La Nature._

* * * * *

[Continued from SUPPLEMENT, No. 622, page 9935.]

THE CHANGE OF GAUGE OF SOUTHERN RAILROADS IN 1886.[1]

[Footnote 1: A paper read before the Western Society of Engineers,
June 7, 1887.]

By C.H. HUDSON.

Many of the wheels that were still in use with the long hub were put
into a lathe, and a groove was cut an inch and a half back from the
face, leaving our cast collar, which was easily split off as before.
(Fig. 24.)

With tender wheels, as with our car wheels, the case was different.
Originally, the axle for the 5 ft. gauge was longer than for the 4 ft.
9 in.; but latterly the 5 ft. roads had used a great many master car
builders' axles for the 4 ft. 9 in. gauge, namely, 6 ft. 111/4 in. over
all, thus making the width of the truck the same as for 4 ft. 9 in.
gauge. To do this a dished wheel, or rather a wheel with a greater
dish by 11/2 in. than previously used, was needed, so that the tread of
the wheel could be at its