275 



tudinal dyke was more likely to be undermined, and fail of 

 its object, than the transverse dyke. This latter had a con- 

 stant tendency to strengthen itself, by causing the deposi- 

 tion of matter in its vicinity. These transverse dykes 

 should be made to slant up stream. Their distance apart 

 should be in inverse proportion to the velocity of the cur- 

 rent. Mr. von Steinwehr exhibited drawings of these dykes 

 constructed in different ways, and explained the practical 

 method of constructing them. 



In conclusion, Mr. von S. explained to the Institute the 

 improvements made in the navigation of the Vistula under 

 the direction of the Prussian engineers. The difficulties to 

 overcome were here very great; but such was the excel- 

 lence of the method adopted, that it has proved perfectly 

 successful. Mr. von S. exhibited charts of the river Vistula 

 before and after the improvement. 



At the close of the paper, Mr. DeWitt mentioned an in- 

 stance in this connection in the state of Wisconsin, in which 

 the Hollanders had succeeded by fascine work in stopping 

 the advance of water. 



Adjourned. 



November 15, 1859. 

 The president, Hon. J. V. L. Pruyn, occupied the chair. 



Mr. Strong, Mr. Averill and Mr. Wilson, proposed at the 

 last meeting, were elected. 



Dr. Hough proposed Dr. P. Carpenter of Waring, a cor- 

 responding member. 



Prof. Murray proposed M. H. Bright and A. K. Shepard, 

 as resident members. 



The committee appointed at the session of last winter to 

 superintend the binding of a number of pamphlets, reported 

 their work as nearly complete, and that by the next meet- 

 ing the volumes would probably be in the library. 



Dr. Hough made some remarks to the Institute in illus- 

 tration of the French colony of Castorland. It was settled 

 on Black River in Lewis county, on land granted to Alex. 



