Determination of Very Small Amounts of Carbon in Metals ROBERT
E.
FRYXELL
General Electric Co., Pittsfield, Mass.
b The precision of methods that involve exposure of crucibles to the atmosphere is normally inferior to the low pressure combustion method a t This limitacarbon levels < O . O O ~ ~ O . tion is the result of residual crucible blank even after prefiring a t 1 100' C. Stabilization of this blank by controlling the combustion temperature with a variable transformer significantly improves the precision of measurement. For the 7 0 analysis of metals containing
