Proceedings of the Polytechnic Association. 959 



■vraut to pass in or ont. On best autlioritj we find that at least one 

 and one half hours, on an average, passes away during the rise and 

 slack water, and fall of the first half inch, at full tide, and when the 

 motion of the water is scarcely felt. Probably a still longer time 

 could be used, because the high tides will be at the navy yard and 

 at Governor's Island at a diiFerent period of time, say one hour or 

 more apart, and when the sails have reached the other end of all the 

 basins (which can be passed regardless of the outside waters, it not 

 being proposed to have any gates on the interior lines), the outside 

 high tide will soon let them through, and thus, probably, not more 

 than two hours will be consumed in the whole passage. If either 

 open flowage of tides, or a system of locks is found to be better than 

 flood gates, they can be adopted. We admit that in either arrange- 

 ment there would be some delay beyond the time now consumed in 

 passing this part of East river, particularly when free from ice ; but 

 it will be more than made up by the stillness of the waters which the 

 dykes will cause at Hellgate and elsewhere, thus enabling vessels to 

 pass on without their present stoppages ; so that, in reality, the dykes 

 will hasten, rather than retard the passage of vessels between Gover- 

 nor's Island and Throg's Neck, or Long Island Sound; and in freez- 

 ing times, they will do them a great additional service by keeping ice 

 away, as will presently be shown. Suppose, however, that there is 

 some delay, and that some of these sloops and schooners are com- 

 pelled to wait, even a whole day, or go outside of Long Island, or 

 through a Harlem canal, are we to relinquish a vast good which the 

 docks would confer on the many, simply because this comparatively 

 small interest, large as it is, might be put to a little inconvenience? 

 In the language of the Coast Survey, "we are not to forego docks, 

 wharves, and piers, &c. (to which we may add good harbor entrances, 

 and great highways of land travel) " the very means and instruments 

 by which the use of the" harbor is established, because wherries and 

 small craft cannot stem the current " (or be put to some delay). No ; 

 as well might a man refuse to eat, and preserve his life, because his 

 hand might be put to some trouble in conveying food to his mouth. 

 "We should rather seek for the greatest good to the united interest of 

 all concerned and govern ourselves accordingly in these public works. 

 On the second objection, the liability to freeze, we have only to 

 instance the experience of the Atlantic dock, Brooklyn, to whose 

 superintendent this plan has been submitted ; and he says that we 

 need not fear any serious trouble from that cause. Of their own dock 



