Haupt.] ^ ^^ [Jan. 18, 



nent exists and has the power attributed to it, which it is necessary that 

 maritime engineers should recognize in designing successful works of 

 improvement. 



The existence of such a force as that described, and the effects produced 

 thereby, in transporting heavy articles, and, a fortiori, lighter ones, is 

 still further abundantly attested by the following record of observed facts 

 by competent persons. The extracts in Appendix "A" are cited to 

 establish, as the author says, a '^fundamental princi2'>le, that the, deposits 

 on the ocean border are only made by the current of the flood: tide," and are 

 a complete confirmation of the conclusions I have reached from an inde- 

 pendent and somewhat different line of reasoning, based upon a compre- 

 hensive comparative study of the coast charts. 



They were compiled by the late Rear- Admiral Davis,* one of the 

 most talented hydrographers this country has produced, and were ac- 

 cepted by such eminent authorities as Profs. Henry, Agassiz and Guyot, 

 but were unknown to me until mj'' attention was drawn to them by this 

 discussion. 



(C) VELOCITY INSUFFICIENT ? 



" It rests with Prof. Haupt to demonstrate that his tidal currents flow 

 along the shores of these hays with a velocity sufficient to move the materials 

 forming the bars, and this he has failed to do. ' ' 



It would appear from this opinion of the Board that they expect the 

 results produced by the flood to be those due wholly to the velocity of the 

 littoral currents, evidently overlooking those other and far more potent 

 agencies which are at work in the flood, as previously proved with refer- 

 ence to New York entrance. I have, in general, designated this force as 

 the "littoral component," but it has been confused with and mistaken for 

 the littoral current, and since the velocity of the latter is evidently small, 

 it has been concluded that there can be no motion produced by this flood 

 component. I have already cited numerous unmistakable instances of sucli 

 motion and deposit in opposition to the prevailing wind theory, and will 

 now merely call attention to the fact that these results may be produced 

 even without any littoral current, since matter may be given a motion of 

 translation without the motor itself having such a motion. For example, 

 the usual helices for mixing concrete, transport the material from one 

 end of the trough to the other, even against gravity, merely by the rota- 

 tion of the axis, and water is raised by the Archimedean screw in a similar 

 manner. The dynamic action of the waves racing along the beach is pre- 

 cisely the same. If the wave of translation, as it comes rolling in, does 

 not strike normally (and in a bay it will generally be oblique), then it will 



* Clias. Henry Davis, LL.D., U. S. N., was born in Boston, Mass., Januarj^ 16, 1807, and 

 entered the navy as midshipman in 1823, becoming Rear-Admiral in 1863. In 1861, he 

 was a member of a board to report upon the condition of the harbors and inlets of the 

 Southern coast. In 1859 he was made Superintendent of the " Nautical Almanac ;" in 

 1865, of the Naval Observatory, and during his active scientific and professional life, he 

 translated the " Mteanique C61este." 



