โ Scribed by C.
No coin nor oath required. For personal study only.
fI~ '(di~.7 BoilcJ's by Eb~ctri('it[/. 189 the boiler itself--it may be in the arrangement of the flues, ill the manner of feeding, or in the forced eonlbustion, in which eases the leaks will continue to break out as often as they are stopped. Adding another boiler often stops the leaks of the others.
2d. The humidity present at the front of boilers, and which is carried into their flues by the draught when the boilers are out of use.
I have witnessed cases where a gutter passing in front of boilers received their water when run out. This gutter also received the discharge from several gauge-cocks, so that aqueous vapor was always , rising from it. After some tinle all the boiler plates were notably rusted.
In other cases the boiler water was run out into the ashpit, during which operation the aqueous vapor entered the flues, diluted the acid products, and, at each time the boiler was allowed to cool, pitted its plates a little. A cause of humidity that only operates occasionally suffices to destroy a boiler at the end of several years.
3d. The natural or artificial humidity of the flues. Above all, it is necessary that water should not enter the flues whel~ the boiler is ran out or emptied, because they would then continue humid all the time the boiler remained out of use, and the corrosion would rapidly go on. It is also necessary to prevent any water that may fall on the masonry or setting of the boiler from entering the flues.
4th. The too low temperature of some of the flues.
If the hygrometric state of the gases of combustion be such that the aqueous vapor they contain can condense on the heating surfaces of the boiler or of its feed-water heater, these surfi~ces will remain constantly humid and rust very rapidly.
5th. When the flues of a boiler out of use are in communication with the flues of another boiler in use, the acid vapors in the gases of combustion from the latter will condense on the heating surfhccs of the former.
Heating Boilers by l!llectricity.--Charles Davis, of Paris, proposes to fasten a number of spirally wound platinum wires in an ordinary steanl boiler, and to send through them an electrical current of sufficient strength to boil the water. He does not say how he will produce the requisite amount of electricity, nor at what cost per horse power he expects to furnish the steam.--Dingler's Jour.
C.
๐ SIMILAR VOLUMES
Paint for Seawater Vol. 118, No. 12.) This form of protection has been found desirable on some of the waterfront structures erected and maintained on San Francisco Bay by the Board of State Harbor Commissioners. The impervious protective coating is the result of many years testing. It is a compound