General Electric engineer Ernst Alexanderson designed a ten-thousand-cycle alternator for the first successful radio transmission at Brant Rock, Massachusetts, in 1905.

Wilbur O. Atwater of the U.S. Department of Agriculture invented the respiratory calorimeter in 1904.

In 1909 Belgian-born chemist Leo Hendrik Baekeland announced the development of Bakelite, a condensed resin that became a standard insulation product.

Edward Binney, a Pennsylvania chemist, developed the Crayola crayon in 1902.

In 1903 Percy Brown established a radiology department, using new X-ray technology, at Children's Hospital in Boston.

Thaddeus Cahill exhibited his electric typewriter at the Pan-American Exhibition in Buffalo in 1901.

In 1906 Willis H. Carrier invented air conditioning. In 1908 Frederick G. Cottrell patented the electrolytic precipitator, an air purifying device that removes particulate materials from factory smokestacks.

In 1901 Reginald Fessenden, an engineering professor at the University of Pittsburgh, invented a highfrequency alternating current generator.

Yale physics professor Josiah Willard...