Complex sentence: The prototype was built by J. S. Leggett and Stearn's engineer, F. L. Corey, and was an electric model which sold so few models through 1900 that the company changed to steam power in 1901.
Split into simpler sentences: The prototype was built by J. S. Leggett and Stearn's engineer, F. L. Corey, and was an electric model. The automobile sold so few models through 1900 that the company changed to steam power in 1901.