boiler can be
run continually and regularly at higher overloads, with higher
efficiency, and lower upkeep cost than any other boiler on the market.
It is especially adapted for power-plant work where it is necessary to
use a boiler in which steam can be raised quickly and the boiler placed
on the line either from a cold state or from a banked fire in the
shortest possible time, and with which the capacity, with clean feed
water, will be largely limited by the amount of coal that can be burned
in the furnace.

The distribution of the circulation through the separate headers and
sections and the action of the headers in forcing a maximum and
continuous circulation in the lower tubes, permit the operation of the
Babcock & Wilcox boiler without objectionable priming, with a higher
degree of concentration of salts in the water than is possible in any
other type of boiler.

Repeated daily performances at overloads have demonstrated beyond a
doubt the correctness of Mr. Babcock's computation regarding the
circulating tube and header area required for most efficient
circulation. They also have proved that enlargement of the area of
headers and circulating tubes beyond a certain point diminishes the head
available for causing circulation and consequently limits the ability of
the boiler to respond to demands for overloads.

In this lecture Mr. Babcock made the prediction that with the
circulating tube area proportioned in accordance with the principles
laid down, the Babcock & Wilcox boiler could be continuously run at
double its nominal rating, which at that time was based on 12 square
feet of heating surface per horse power. This prediction is being
fulfilled daily in all the large and prominent power plants in this
country and abroad, and it has been repeatedly demonstrated that with
clean water and clean tube surfaces it is possible to safely operate at
over 300 per cent of the nominal rating.

In the development of electrical power stations it becomes more and more
apparent that it is economical to run a boiler at high ratings during
the times of peak loads, as by so doing the lay-over losses are
diminished and the economy of the plant as a whole is increased.

The number and importance of the large electric lighting and power
stations constructed during the last ten years that are equipped with
Babcock & Wilcox boilers, is a most gratifying demonstration of the
merit of the apparatus, especially in view of their sat