Winslow —The Mapping of Missouri. 75 
The longitude of St. Louis is about 93° W. from Paris (903° 
W. from Greenwich ). 
The Duvallon map of 1802, is in the ‘* Vue de la Colonie 
Espagnole du Mississipi,’ etc., 1802, B. Duvallon, editor 
and author. The longitude of St. Louis is placed at 743° W. 
of Isle de Fer (924° W. of Greenwich). 
The Lewis and Clarke expedition from St. Louis to the 
Pacific coast was conducted during the years 1804 to 1807. 
This may be considered the first definitely recorded survey of 
the Missouri river. The expedition started at St. Louis and 
proceeded up the Missouri river in keel boats. The explorers 
were provided with compasses, chronometers, sextants and 
artificial horizons. 
Various editions of the resultant reports were published. 
Three of these have been consulted by the writer. The first 
was issued in London in 1809, under this title: ‘* The 
Travels of Capts. Lewis and Clarke from St. Louis by way of 
the Missouri and Columbia Rivers to the Pacific Ocean per- 
formed in the years 1804, 1805 & 1806 by order of the 
Government of the United States containing,’’ etc. ‘* Com- 
piled from various Authentic Sources and Original Docu- 
ments,’’ etc. — ‘ Illustrated with a map of the country in- 
ee ee emer eee Pie yepapars: 
Fic. 10. LEWIS AND CLARKE MAP — 1804 To 1806. 
Edition of 1809. 
Initial Merid., at Greenwich. 
