What methods did Lewis and Clark use to determine
their geographic position?
The
Lewis and Clark expedition utilized a number of navigational tools that
were common in their day. Ascertaining latitude and longitude was accomplished
using a sextant, and octant, a chronometer, and several types of artificial
horizons. In addition to these instruments, the expedition carried a circumferentor,
or surveying compass. The latter was utilized to find the difference between
magnetic north and true north. While imperfect by the standards of today’s
global positioning systems, they did allow the Corps of Discovery enough
certainty to have a relatively good idea where they were at any given
time. Nonetheless, a mistake of two degrees in calculations could mean
an error of up to one hundred miles. Since they were in unknown parts
anyway, this was not to provide a problem that could not be solved.
The
Lewis and Clark expedition utilized a number of navigational tools that
were common in their day. Ascertaining latitude and longitude was accomplished
using a sextant, and octant, a chronometer, and several types of artificial
horizons. In addition to these instruments, the expedition carried a circumferentor,
or surveying compass. The latter was utilized to find the difference between
magnetic north and true north. While imperfect by the standards of today’s
global positioning systems, they did allow the Corps of Discovery enough
certainty to have a relatively good idea where they were at any given
time. Nonetheless, a mistake of two degrees in calculations could mean
an error of up to one hundred miles. Since they were in unknown parts
anyway, this was not to provide a problem that could not be solved.