Issues for 1929- include section Contents noted (1929-1939 called Metallurgical abstracts; Jan. 1940- Sept. 1945 called Engineering digest; Oct. 1945- called Materials a methods digest) Annual indexes of the abstracts and digest were prepared 1929-1941; beginning in 1942, included in the complete index to the periodical.Automatic ignition was applied in 1930 by the Submerged Combustion Co. but not sold commercially until 1937. Controlled by a mercury switch, present day burners ... Maintenance costs per burner in one installation has been S70.93 a year for parts. In all, there are approximately ... They were heated to more than 2000Ad, taken directly from the furnace and shoved against an emery wheel. Hot and coldanbsp;...