effect, as, for instance, by using sand the grains of which are round instead of sharp (and such sand can be found), or by using fine sand." "The durability of a steel structure will depend upon the quality of the metal, upon its mass, and the measures taken to prevent its deterioration; and its strength, measured either by the stress it will bear or by its resistance to corrosion, is only the strength of its weakest member."

Steel differs from wood, brick, etc., in that there is much less absorption of the paint into its body, so that the adhesion of the first or foundation coating of paint upon steel is necessarily almost wholly restricted to its surface, and the adhesion of subsequent coats is restricted to the surface of the dried paint already in position. "The better adhesion of paint  to  puddled iron