the self-taught engineers of the erie canal -- 7/26/16
Today's selection -- from Heaven's Ditch by Jack Kelly. We often assume that a workforce needs to be highly educated to propel an economy forward. Often, it is the opposite; It is economic opportunity that compels a workforce toward more education. So it was with the Erie Canal, by far the greatest engineering project of its day, and one of the greatest in history to that point. The problem was that there were very few trained engineers:
"The goal [in construction of the Erie Canal] was to find a path west that was as level as possible and as straight could be managed. Hills and valleys were both to be avoided. Once [Benjamin] Wright determined a likely direction, his surveyor sighted on a distant object, took a compass reading, and walked toward the landmark. An axman accompanied him, notching trees along the trail. Two additional woodcutters hacked down brush and trees to clear a four-foot-wide path. Men carrying sixty-six-foot-long chains measured a section almost the length of a football field. They marked each end with two stakes, one extending above the ground, the other flush with the soil.
Profile of the original Erie Canal
"An assistant engineer next set a level on a tripod halfway between these points. Two rodmen rested graduated poles upright on each of the flush stakes. The engineer put the crosshairs of his device on each pole. He noted the difference in elevation, if any, between the stakes. His reading had to be precise to the fraction of an inch. Any errors would accumulate, throwing off the final calculation.
"Meanwhile, Wright would be examining the terrain: streams, property lines, rocks, knolls, drainage. The survey and investigation would eventually be translated into a detailed map of the route. Cost was always on the engineer's mind. Aqueducts to cross streams, locks to navigate elevation changes, embankments to carry the canal over low stretches, all would be expensive. Periodically, Wright directed his men to dig ten-foot-deep holes in order to examine the nature of the soil. He was always on the lookout for sources of water. Would the local streams, lakes, and ponds provide enough water to keep the ditch filled? ...
"The men were learning as they went. Except for West Point, which taught military engineers, no school in America offered courses in engineering. A young farmer named John Jervis was hired by Benjamin Wright as an axman to clear brush and trees. 'The mystery of the level,' he said, 'the taking of sights, its adjustment, and the computations of these observations were all dark to me.' Little by little Jervis learned by doing. In time, he would become a supervisor on the canal, then one of the premier civil engineers in American history.
"While the survey teams did their work, [Erie Canal commissioner and future governor DeWitt] Clinton and the commissioners were drawing up a plan for building the canal. They arrived at a design: the profile of the ditch would be an inverted trapezoid forty feet across at the top, twenty-eight at the bottom, and four feet deep. Locks would be ninety feet long and twelve feet deep, allowing them to raise or lower a boat eight feet.
"Clinton ranged along the route, examining the work of the surveyors as it unfolded. 'The mind is lost in wonder,' he recorded, 'and perplexed and confounded with the immensity of the ideas which press upon it.' "