'94: WISCON'SIN ACADEMY SCIEiS'CES, ARTS, AND LETTERS. 



tremes of excavtion will be about six miles; the river at this point 

 never rises more than seven feet above the level of the gulf, and is 

 seldom lower than the same. The gulf-end is sheltered by the 

 arms of the delta, and by a number of islands, and will give a safe 

 outlet of 26 feet, which is sufficient to admit the largest class of sea- 

 going vessels. Several locations of canals have been advanced, but 

 all seem to be encumbered with the same objections excepting the 

 Fort St. Philip Canal. 



One plan has been to leave the Pass a TOutre six miles inside of 

 its bar and reach deep water to the north; another, of leaving the 

 Southeast Pass about six miles above its bar and make deep water 

 towards the east. Both these plans have this disadvantage; al- 

 though the slope is inconsiderate, j'et without locks, there is a possi- 

 bility of the canals becoming a branch of the Delta; on the other 

 hand, it may be that the stability of the banks is insufficient to sup- 

 port the construction of locks, or resist the pressure during freshets. 



Another plan has been considered, which is the closing of the 

 head of the South Pass by means of a dam, and entering the Pass 

 through a channel from the Southwest Pass. In this case the dif- 

 ficulty would be the keeping open of the mouth of the pass by 

 dredging away the bar which would be thrown up by the ocean 

 waves. It appears to me, that the plan of the Port St. Philip 

 Canal is the most reliable plan of producing uninterrupted naviga- 

 tion to the Mississippi, and the only plan which promises positive 

 success. This canal would be in the extreme six'and one-half miles 

 long and should be 300 feet wide at the bottom, with sloping banks 

 of not less than two horizontal to one perpendicular. The lift 

 to be overcome would never exceed seven feet; the locks should be 

 of the greatest capacity, say 500 feet long and 80 feet wide, so as to 

 enable the largest class of vessels to enter without difficulty, or to 

 pass a fleet of small vessels at the same time. I would recommend 

 at least two locks, in order not to impede navigation in the least 

 degree ; at the same time if one lock should in any manner be im- 

 paired, commerce would not be impeded. 



I have not the slightest doubt that such a canal could be 

 constructed at a cost not to exceed that estimated for the improve- 

 ment of the South Pass, say ^8,000,000 in round numbers with a 

 certainty of success which sio other plan promises. An annual 

 expenditure of |25,000 or §30,000 may be required to maintain the 



