1. The letter, addressed to Harry L. Hopkins, Administrator of the Works Progress Administration (WPA) is included in the report, G. Perazich, H. Schimmel and B. Rosenberg, Industrial Instruments and Changing Technology, Work Progress Administration, National Research Project, Report No. M-1 (Philadelphia, PA.: GPO, 1938), reprinted in I. Bernard Cohen, ed., Research and Technology (New York: Arno Press, 1980). The Work Progress Administration was the government body which administered the projects set up under the various “New Deal” acts. After 1939, it was called the Works Projects Administration.
2. Although the data given are based on a sample of seven major companies, and sales data for all the companies was not available for the whole period, the sales figures given are believed to be representative of the industry as a whole; see Ibid., Appendix C.
3. This data, from the WPA survey, needs interpreting with care since the prices for general machinery may have fallen relative to instrument prices.
4. Instruments, 11 (1936), supplement “Index of Instruments.” This journal, devoted to industrial instruments, was founded in 1929.
5. Historical Record of the Census of Production 1907 to 1970 (London: HMSO, 1978), p. 88.