COMMITTEES ON BEHALF OF THE GOVERNMENT 253 
of the San Juan River in 1873, was not at all hopeful that the 
suggestions of the committee could be carried into effect. He 
remarks in his report: 
“A committee of the National Academy of Sciences in 1867 proposed, as a 
partial remedy for the decay of the river and harbor, the dredging out of the 
channel of the Lower San Juan and the construction of a weir from Leaf’s Island 
to Concepcion Island. The latter of these is in the main river, near its right bank, 
and above the forks. The former has now become joined to the angle or point of 
the mainland between the two branches. Concepcion Island is 2,000 feet from the 
point. The strongest part of the current runs between the two. ‘The island is 
constantly cutting away at one place and forming at another, being composed 
entirely of silt banked around drift-logs which have lodged in the shoal water. 
“The weir, if indeed it could be constructed at all with such a combination of 
unfavorable conditions, viz., the depth and strength of the water, and the yielding 
character of the bottom, would be quite as likely to fail in as to effect, the object in 
view, i. e., the turning of the current into the Lower San Juan, unless the latter 
was dredged out to a sufficient width and depth to prevent, by drawing it away, 
the water from cutting around the dam. ‘This would have to be done for a dis- 
tance of thirteen miles. I confess myself to have been very much discouraged 
when these facts and convictions impressed themselves on my mind.” ®° 
On account of these conditions, he proposed to eliminate the 
Lower San Juan and carry the traffic in a canal which should 
leave the river at a point about 42 miles from the coast. Recent 
maps indicate that this plan, with various modifications, was 
generally accepted down to the time when the interest in an 
interoceanic canal shifted from Nicaragua to Panama. 
COMMITTEE ON THE PROTECTION OF COAL MINES FROM 
EXPLOSION BY MEANS OF ELECTRICITY. 1870 
In the Proceedings of the Academy mention of this committee 
is made under date of April, 1870, in the following terms: 
“ Mr. Gould reported in behalf of himself and Mr. Ferrel, the Committee on 
the letter of Mr. Fua, of Padua, addressed to the President of the United States, 
in reference to the protection of Coal Mines from explosion by electricity, and 
referred by him to the Academy, ‘ That the same communication has been made to 
“Report of Explorations and Surveys for a Ship Canal through Nicaragua, 1872-73, 
p-. 61. Sen. Exec. Doc. no. 57, 43d Congress, 1st Session. 
18 
