14 



ing the winter and spring in the valley, they collect in the morn- 

 ing and last until the sun dissipates them: they preserve the 

 valley from the chilling frosts, and render its climate milder 

 than that of the adjacent country. The prevailing winds are 

 wcsterly,and four times out of five a breeze blows up the stream, 

 following the meanders of the valley: it is a deviated branch 

 of the Mexican trade wind. Thunder storms are frequent in 

 summer, and hurricanes have sometimes happened. Waves 

 then rise high against the current and are dangerous. Inter- 

 mittent fevers are not uncommon in the fall near some low banks 

 and in the low bottoms; but the climate is otherwise, very 

 healthy. Many springs are found along the banks and cliffa 

 and many more appear at low water. 



Scenery. All the banks, and cliffs, and nearly all the islands 

 are covered with trees, among which the Platanua occidentals 

 (Sycamore,) the Pofmlus angulata, (Cotton tree,) and the Sa- 

 lix nigra (Willow) are the most common and conspicuous. 

 The cliffs and islands offer every where very fine views and 

 •prospects, and the cultivation increases those natural beau- 

 ties; this is very conspicuous near Cincinnati, Maysvillc, Pitts- 

 burgh, &c. 



Navigation. The River is navigated by Steam boats, Bar- 

 ges, Keel boats, Schooner barges, Rowing boats, Flat boats or 

 Arks, Skiffs, Pirogues, Rafts, &c. of which many thousand an- 

 nually descend the stream. Those which ascend it again a- 

 mount annually to many hundred, among which there are al- 

 ready more than sixty Steam boats, averaging the burthen of 

 150 tons ea-:h. The ascent is effected, besides steam, by sailing, 

 poling, warping,and rowing, and is very tedious. The difficul- 

 ties of the navigation consist in bars, sunken rocks, rocky ledg- 

 es, snags or sunken logs, sawyers or moving snags, drifted logs, 

 planters or upright trees, falling trees, sinking banks, sudden 

 storms, rises and falls, drifting ice, rejecting currents, whirl- 

 pools, shallow water, ripples and rapids, Sic. : but they are not 

 dangerous except at some particular stages of the waters. In 

 the spring rise the water is so deep that it may easily float ves- 

 sels^ of 500 tons, even over the falls. Many large ships were 

 built at Pittsburgh and Marietta, which safely reached the sea; 



