The average low temperature for January 1952, was 11 degrees Fahrenheit. This was mild weather as compared to the subzero readings of the previous winter. Only 10 slight frostbite cases were reported for the month in contrast to the 3,083 nonbattle casualties, nearly all frostbite cases, incurred during the two weeks (27 November to 10 December 1950) of the Chosin Reservoir breakout. The improvement in January 1952 could not be credited entirely to more clement weather. It was due in greater measure to one of the most noteworthy innovations of the Korean war--the insulated rubber combat boot, which proved much superior to the shoe pac of the past winter. U.S. Army experiments dated back to 1944. They were dropped three years later after efforts to perfect a boot with sealed insulation failed to meet the test of long marches. The Navy had more promising results with the boot during the winter of 1948–1949 when Arctic clothing tests were conducted at Point Barrow, Alaska. Army and Navy tests at Mt. Washington, New Hampshire, the following winter were inconclusive. Marine Corps tests were held during the first four months of 1951 at the following places: MCEB, Quantico; Fort Churchill, Manitoba; Big Delta, Alaska; Pickel Meadows, California; and the Naval Medical Field Research Laboratory (NMFRL), Camp Lejeune. “In addition to engineering tests,” states the Marine report, “the insulated rubber boots have been worn by test subjects selected from a variety of backgrounds; under conditions of activity varying from strenuous marching for 20 miles to complete immobility; in ambient temperatures from 58° to -42° F.; over terrain ranging from soft snow [to] hard snow, ice, sand, rocky ground, mud, gravel, water, and iced river banks; for periods of time corresponding to a normal working day and more than 72 hours. As now constructed, the insulated rubber boot, employing the vapor barrier principle, meets the requirements outlined previously and is satisfactory for use by Marine Corps ground troops in cold climate areas, supplanting the shoe-pac combination....”[345] [345] LtCol G. W. Hardwick, “Summary of Marine Corps Experience with IRB [Insulated Rubber Boot], Rpt of 8 May 1951.” Other sources for the development of the boot, also found in G-4 files, Headquarters Marine Corps, are as follows: G. E. Folk, Abstract of Bowdoin College Rpt, Jun 1951, “The Penetration of Water into the Human Foot;” G-4 Rpt, “Resume of Activity re Insulated Rubber Boot,” 7 Feb 1952; G-4 Rpt, “Boot, Rubber, Insulated, Cold Weather,” 28 Nov 51; G-4 Rpt, “Fact Data Sheet, Boot, Insulated, Rubber,” n.d.; MajGen J. T. Selden memo to CMC, 26 Apr 52.