In view of this, the details of actual consumption of gas on a regular customer's order job will be of interest. The "Revergen" furnace, manufactured by the Davis Furnace Company, Luton, Bedford, England, was used on this job, and is provided with regenerators and fired with illuminating gas at ordinary pressure, the air being introduced to the furnace at a slight pressure of 3 to 4 in. water gage. The material was charged into a cold furnace, raised to 1,652 deg.F., and maintained at that temperature for 8 hr. to give the necessary depth of case. The work consisted of automobile gears packed in six boxes, the total weight being 713 lb. The required temperature of 1,652 deg.F. was obtained in 70 min. from lighting up, and a summary of the data is shown in the following table: Cubic Foot Total Per Pound Number of of Load Cubic Foot Gas to raise furnace and charge from cold to 1,652 deg.F., 70 min. 1.29 925 Gas to maintain 1,652 deg.F. for 1st hour 0.38 275 Gas to maintain 1,652 deg.F. for 2nd hour 0.42 300 Gas to maintain 1,652 deg.F. for 3rd hour 0.38 275 Gas to maintain 1,652 deg.F. for 4th hour 0.42 300 Gas to maintain 1,652 deg.F. for 5th hour 0.49 350 Gas to maintain 1,652 deg.F. for 6th hour 0.49 350 Gas to maintain 1,652 deg.F. for 7th hour 0.45 325 Gas to maintain 1,652 deg.F. for 8th hour 0.45 325 The overall gas consumption for this run of 9 hr. 10 min. was only 4.8 cu. ft. per pound of load. THE CARE OF CARBURIZING COMPOUNDS Of all the opportunities for practicing economy in the heat-treatment department, there is none that offers greater possibilities for profitable returns than the systematic cleaning, blending and reworking of artificial carburizers, or compounds. The question of whether or not it is practical to take up the work depends upon the nature of the output. If the sole product of the hardening department consists of a 1.10 carbon case or harder, requiring a strong highly energized material of deep penetrative power such as that used in the carburizing of ball races, hub-bearings and the like, it would be best to dispose of the used material to some concern whose product requires a case with from 0.70 to 0.90 carbon, but where there is a large variety of work the compound may be so handled that there will be practically no waste. This is accomplished with one of the most widely known artificial carburizers by giving all the compound in the plant three distinct classifications: "New," being direct from the maker; "half and half," being one part of new and one part first run; and "2 to 1," which consists of two parts of old and one part new. SEPARATING THE WORK FROM THE COMPOUND