be done with impunity in the case of bridge metal can only be proved by actual experiments with the high alloy thus produced.

An inspection of Table 5m shows that the Carmol and Nichromol steels are out of the running; hence it will be necessary to test the three others.

Comparing Chromol and Nicmol, we have:

From Figs. 5a and 5b we find that this product corresponds to a simple-span length of about 700 feet and to a main cantilever opening of about 1,900 feet, hence it may be concluded that, except for unusually long spans, Nicmol Steel is not as economic as Chromol steel.

Comparing Chromol and Chrovanmol, we have:

As in the last case, this is so great as to show that Chromol steel is more economic than Chrovanmol steel.

From all that precedes it is evident that the most promising combination of alloying materials for a high-grade bridge-steel is one of chromium and molybdenum; and a good analysis to test as a starter would be as follows: