Page:Popular Science Monthly Volume 12.djvu/141



ECTION III. The Period of Development. —22. The evident defects of Savery's engine, its extravagant consumption of fuel, the inconvenient necessity of placing it near the bottom of the mine to be drained, and of putting in several for successive lifts where the depth was considerable, and, especially, the risk which its use with high pressures involved even in its best form, considerably retarded its introduction, and it came into use very slowly, notwithstanding its superiority in economic efficiency over horse-power.

23. The first important step taken toward remedying these defects was by Thomas Newcomen and John Cawley, or Calley, two mechanics of the town of Dartmouth, Devonshire, England, who produced what has been known as the Atmospheric or Newcomen Engine.

Newcomen was a blacksmith, and Cawley a glazier and plumber.

It has been stated that a visit to Cornwall, where they witnessed the working of a Savery engine, first turned their attention. to the subject; but a friend of Savery has stated that Newcomen was as early with his general plans as Savery.

After some discussion with Cawley, Newcomen entered into correspondence with Dr. Hooke, proposing a steam-engine, to consist of a