each horse-power required 30 pounds of steam; if the steam is assumed to
have 25 per cent entrained water due to condensation in the pipes and
connections, then 4,000 pounds steam will need be produced in the
boilers, or 1,000 pounds more than necessary. To produce this steam will
require about 125 pounds of good coal per hour, or 1,000 pounds per day
of eight hours. One-half ton per day at $3 per ton for 300 days, $450.
The actual cost of the covering put on complete probably did not exceed
$150."

An interesting verification of the remarkable non-heat condensing
quality of the magnesia covering occurred at Lynn, Mass. In the heart of
the district in that city, recently the scene of the disastrous
conflagration, there was located the machine-shop of Messrs. Rollins &
Glozier. A two-inch steam-pipe there was covered with this material. The
heat of the fire at this place has been curiously determined to have
been between the minimum extreme of 2,756° Fah. and the maximum extreme
of 2,950° Fah., in this way: Cast-iron melts at 2,756° Fah.;
wrought-iron at 2,950° Fah. A portion of the cast-iron bed of a lathe
was fused into an irregular mass, and on it, partly imbedded, was a
wrought-iron nut not melted. The steam-pipe spoken of fell a distance of
20 feet, and some of the magnesia covering was broken by the fall, but
so effective was its heat-resisting and non-heat-conducting power that
the pipe was found to be uninjured, and it is being used again in the
building which is being erected to take the place of the one burned.
That the magnesia should have endured the ordeal successfully was not
unexpected, for we know that it is used by the Herreshoff Manufacturing
Company as a lining to the shells of its coil boilers, and it is there
subjected to a very intense heat resulting from the forced draught used
in this type of boiler. Instances could be multiplied indefinitely, but
I refrain from occupying further time with them, citing, however, one