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The Locomotive - Lighthouse Survival Blog

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20 THE LOCOMOTIVE. [February,<br />

could be iuferred with considerable precision. It will be impossible to give the results<br />

of these tests in detail in this place, but the foregoing abstract of five of them shows<br />

quite well that the strength of steel is greater at about 500° Fah. than it is at 70°. <strong>The</strong><br />

temperatures are all on the Fahrenheit scale.<br />

<strong>The</strong>se five series of tests were made with five difl^erent qualities of steel, containing,<br />

respectively, .09, .20, .31, .37, and .51 per cent, of carbon. <strong>The</strong> figures given in the<br />

columns headed "Percentage of Strength" were obtained by dividing the tensile<br />

strength of a samj^le of steel at the given temperature by the strength of the same quality<br />

of steel at 70° Fah.<br />

:<br />

It will be seen that these specimens were all stronger in the neighborhood of zero<br />

than they were at ordinary temperatures; and that, in fact, they all show a minimum of<br />

strength at 210°, or thereabouts, and a maximum of strength at about 550°. This<br />

curious property of iron may now be considered to be well established ; and it deserves<br />

further attention than it has yet received.<br />

Inspectors' Report.<br />

November, 1892.<br />

During this month our inspectors made 6,013 inspection trips, visited 12,457 boilers,<br />

inspected 4,621 both internally and externally, and subjected 714 to hydrostatic press-<br />

ure. <strong>The</strong> whole number of defects reported reached 9,952, of which 1,029 were considered<br />

dangerous ; 40 boilers were regarded unsafe for further use. Our usual summary<br />

is given below<br />

Nature of Defects.<br />

Cases of deposit of sediment.<br />

...<br />

-<br />

Cases of incrustation and scale,<br />

Cases of internal grooving, ...<br />

....<br />

Cases of internal corrosion, - - -<br />

Cases of external corrosion,<br />

Broken and loose braces and<br />

....<br />

stays, -<br />

Settings defective, - . . - -<br />

.....<br />

Furnaces out of shape,<br />

Fractured plates, - . . - -<br />

Burned plates,<br />

...<br />

Blistered plates, . . . . -<br />

Cases of defective riveting, - - - -<br />

Defective heads, . . . - -<br />

Serious leakage around tube<br />

....<br />

ends,<br />

Serious leakage at seams,<br />

Defective water-gauges,<br />

....<br />

Defective blow-offs, . . _ .<br />

Cases of deficiencj' of water, . . -<br />

Safety-valves overloaded,<br />

Safety-valves defective in construction.<br />

Pressure-gauges defective, . . . -<br />

Boilers without pressure-gauges, . - -<br />

Unclassified defects, . . - - .<br />

Whole Number.

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