1 For 1937, excludes establishments primarily engaged in producing lawn sprinklers, spun ware, nonferrous metal novelties, tackle blocks, aluminum ornamental work, aluminum stampings, and machine knives (except metalworking) and includes establishments primarily engaged in making caulking guns, toilet seats, brooders, cast aluminum cooking ware, and hair clippers. In 1939, value added by manufacture on a basis comparable with 1937 was $1,340 million. 2 Includes electrical machinery.

For 1937, includes establishments primarily engaged in manufacture of thermostats and gauges, heat treating of steel, machine knives, and tackle blocks, and excludes establishments primarily engaged in manufacture of vacuum cleaners, turbo-generators and water-wheel generator sets, hair clippers for animal use, brooders, nonferrous bearings, certain industrial furnaces and ovens, time-stamps and time-recording machines, dictating machines, certain valves and fittings (except plumbers'), and caulking guns. In 1939, value added by manufacture on a basis comparable with 1937 was $1,990 million.

1 Beginning 1958, includes establishments primarily engaged in manufacture of household refrigerators and home and farm freezers; household laundry equipment and sewing machines; water heaters, except electric; and other household appliances. Excludes those primarily engaged in manufacture of hearing aids; high frequency, induction, and dielectric heating apparatus; commercial food warming equipment; industrial electric heating units and devices; and insulated wire and cable made from purchased wire. 2 Included with machinery, except electrical.

3 Beginning 1947, includes establishments primarily engaged in manufacture of electric (dry) shavers.

Beginning 1939, excludes establishments primarily engaged in manufacture of vacuum cleaners, turbo-generators and water-wheel generator sets, dictating machines and electric industrial furnaces and ovens. In 1939, value added by manufacture on a basis comparable with prior years was $1,000 million.

$ Beginning 1935, excludes establishments primarily engaged in manufacture of certain types of beauty and barber shop equipment.

Beginning 1927, excludes establishments primarily engaged in manufacture of certain types of mechanical refrigerators.

7 Beginning 1909, excludes establishments primarily engaged in manufacture of signs and advertising novelties.

8 Beginning 1958, includes establishments primarily engaged in manufacture of truck and bus bearings, convertible tops for automobiles, rebuilt automotive parts, and aircraft and related engine and power take-off gears and excludes those primarily engaged in manufacture of parachutes.

For 1937, includes railroad repair shops. In 1939, value added by manufacture on a basis comparable with 1937 was $1,794 million.

1 Beginning 1958, includes establishments primarily engaged in manufacture of laboratory precision balances, laboratory furniture, revolution counters, operating room and other hospital furniture, surgical corsets, and hearing aids and excludes those primarily engaged in manufacture of sanitary napkins and tampons.

2 For 1947 and 1954-1970, includes establishments primarily engaged in manufacture of automatic temperature controls.

Beginning 1939, includes establishments primarily engaged in manufacture of thermostats and gauges and excludes those primarily engaged in manufacture of timerecording stamps and machines. In 1939, value added on a basis comparable with prior years was $314 million.

Beginning 1937, includes establishments primarily engaged in manufacture of certain mechanical measuring instruments. In 1937, value added by manufacture on a basis comparable with prior years was $295 million.

5 Beginning 1935, includes establishments primarily engaged in manufacture of certain dental equipment and supplies (chairs, cabinets, and electrical devices).

• Beginning 1929, excludes establishments primarily engaged in manufacture of gas machines. In 1929, value added by manufacture on a basis comparable with prior

years was $306 million. 7 Beginning 1927, excludes dental laboratories operating on a custom basis. In 1927, value added by manufacture on a basis comparable with prior years was $280 million.

Beginning 1925, excludes establishments primarily engaged in grinding lenses for spectacles and eyeglasses to individual prescription.

Beginning 1914, includes establishments primarily engaged in manufacture of motion-picture machines. In 1914, value added by manufacture on a basis comparable with prior years was $96 million. 10 Includes ordnance.

11 Beginning 1958, excludes establishments primarily engaged in manufacture of plastics products not elsewhere classified, cork products, soda-fountain and bar equipment, and jewelry, instrument, and musical instrument cases and includes those primarily engaged in manufacture of linoleum and other hard surface floor covering, n.e.c. 12 Prior to 1955, includes ordnance and accessories.