378 Expedition to the 



;lrc far more numerous and formidable than those of the lat- 

 ter. The channel is rendered exceedingly intricate by means 

 of sand-bars and islands, and the navigation, in many places, 

 is very hazardous on account of the multiplicity of rafts, 

 snags, sand-bars, &c., with which the channel is beset. No 

 part of the river is exempt from these obstructions, for any 

 great distance, particularly when the water is low. 



As this river in connection with some of its principal tri- 

 butaries, traverses a considerable variety of climates, embra- 

 cing more than ten degrees of latitude, a series of spring fresh- 

 ets invariably takes place, maintaining an elevated stage of 

 water, from the breaking up of winter, early in March, to the 

 middle, and sometimes the last of July, when it is terminated 

 by the summer freshet yielded by the most northerly of its 

 tributaries. During this period, there is a sufficient depth of 

 water to admit boats of almost any burden; but during the 

 residue of the year, it can hardly be called navigable, except 

 for boats, drawing no more than twenty-five or thirty inches. 

 The river is usually blocked up with ice during the winter 

 season. The average velocity of its current in a middle 

 stage of water, may be estimated at four and a half miles, 

 and in time of a high freshet, it moves with an accelerated 

 velocity, equal to five or five and a half miles per hour. 



The Ohio river, as before hinted, differs from those just 

 described, in the rapidity of its current, the width of its bed, 

 character of its channel, and in several other respects. But 

 as its general character is well known, a few remarks in re- 

 lation to it, will here suffice. The obstructions to its naviga- 

 tion are sand-bars, some few rafts and snags, and rapids, to 

 which the intricacy of its channel in several places, may be 

 added. During a middle and high stage of water, these ob- 

 structions entirely disappear, and an accelerated current is 

 the only difficulty to be encountered. The average velocity 

 of the current in a moderate stage of water may be estimated 

 at two and a half miles, and in a high stage at three miles 

 per hour. The season in which the navigation of the Ohio 

 can be relied on, commences between the middle of Febru- 

 ary and first of March, and continues to the latter part of 

 June. A fall freshet usually takes place in October or No- 

 vember, and the river is again navigable for a few weeks. 

 During the rest of the year, boats of inconsiderable burden 

 meet with numerous obstructions in their progress, from the 

 lowness of the water, and in many places, no channel can be 

 Ceimd of sufficient depth to admit their passage. At the dis- 



