1 3 }• OF THE MISSISSIPPI, 



upwards. This statement is only conjectural, founded upon 

 probable circumstances, having been unable to procure a suf- 

 ficient number of accurate observations to be made at ditLr- 

 ent points. 



When the river is very low, the velocity of the stream is 

 scarcely a mile per hour at Natchez, aud much slower at New- 

 Orleans, probably not above half a mile; but during the time 

 of the inundation from 4 to 5 miles. — It is asserted that the 

 current is swifter during die night than the day; this perhaps 

 might oe accounted for by saying, that there is generally a 

 breeze by day blowing up the river, which opposes the current 

 and dams up the water to a certain degree; and that the night 

 being generally still, the water descends with accelerated velo- 

 city; but another fact is not so easily accounted for,, viz. 

 that saw-mills, which are constructed upon canals leading from 

 the Mississippi, perform more work (caeteris paribus) in the night 

 than in the day, the number of strokes of the saw being found 

 greater in a given time. — The encrease of the specific gravity 

 of water by the coldness of the night will be of no avaU in 

 the solution of this question, because the weight and velocity 

 of water in a lateral canal cannot thereby be encreased. We 

 cannot suppose that the evaporation during the day produces a 

 sensible effect in diminishing the quantity of water, because the 

 water thus diminished in the course of the day arrives at the 

 mill during the night. Is it not rather owing to the perfect 

 stillness of the night, that the machine performs its office with- 

 out any unnecessary agitation or friction, which in the day 

 is greatly promoted by the vivifying influence of the sun, cau- 

 sing a more rapid circulation of the atmosphere, and exciting 

 to motion every body on tiie surface of the earth, whether ani- 

 mate or inanimate? It is known to mariners that toe relative 

 cessation of motion on board a vessel under sail, contributes 

 greatly to the rapidity of her movement. This phenomenon 

 merits a more perfect solution. 



Although the velocity ol the water has been said to be from 

 one to five miles per hour, yet this is to be understood of what 

 may be called the thread oii the current, it being considerably 

 less along the shores, and very frequent counter-currents or ed- 



