_Ten degrees extra heat_ in feed water means one per cent. saving in fuel.
_Before blowing out the boiler_ the engineer or fireman should remove all the fire from the furnace, as a small quantity left in the corners, or attached to the bridge wall, might spring a seam or cause a plate to bulge.
_Every engineer should know_ that unequal expansion and contraction is one of the evils which limit the longevity and endanger the safety of all classes of steam boilers; consequently the blowing out, the refilling, the starting of fires and the regulation of the draught should be done with judgment.
_It is not necessary_ to fill a boiler with cold water above the second gauge cock, as the water expands under the process of the formation of steam and it will be found that there is a sufficiency of water in the boiler when steam is raised.
_Single riveted seams_ are equal to 56% of the original strength of the sheet; double riveted seams are equal to 70%, and triple riveted seams are equal to 85%. Triple riveted seams, however, are very seldom used unless for some special purpose, as they are too heavy and thick, and would burn out rapidly if exposed to fire.
_In making calculations_ on the strength of boilers, the factor 56 should be employed instead of 100, as 44% of the strength of the plate is lost by punching the holes for the rivets.
_It should be understood_ that machine riveted seams in steam boilers are superior to hand made seams, as the machine thoroughly upsets the rivet and brings the two sheets in such close contact as to produce friction between the sheets at the lap, which of itself is an element of strength.
_Boilers do not improve_ by standing idle; they will rust very rapidly.
_Never use sharp chisels_ to cut the scale from boiler plate, as the cutting of the plate does more harm than good. Use only a light hammer.
_In patching a boiler_ be careful not to make a pocket in which sediment may collect to cause another injury to the sheet and never put a steel patch upon an iron boiler as the two metals expanding unequally will induce trouble.
_Never forget_ to allow for expansion when running long lines of steam pipe, whether for heating or power, as the neglect of this precaution leads to the formation of immense crooks or bends in the line of pipe wonderful to behold. There must be a slip joint somewhere in long lines of steam piping, unless expansion is allowed for.