354 ANNUAL OF SCIENTIFIC DISCOVERY. 



to engrave them ; and when engraved they are made public. We 

 have published, within the five years past, twenty-five sheets of maps 

 of a very finished kind. They have been examined by our own citi- 

 zens, and by foreigners ; and I believe with approval in every case. I 

 have carefully compared them with foreign maps, in order to see where 

 we stood, and what we had to learn. The arrangements for this part 

 of the work are not now quite adequate to the demand of the field- 

 work. TThe number of computers, draughtsmen, and engravers requires 

 to be increased. It is almost impossible to get a good map-engraver to 

 come to Washington, as all are employed at home. 



" It is easy to see when the first section of the work may be finished. 

 There are about sixteen stations to the boundary, which could be oc- 

 cupied in two years and a half, at the present rate, making the astro- 

 nomical observations as well as the geodetic. I do not propose to do 

 so, because my time in the spring and autumn is better employed in 

 other positions, and it would be better, therefore, to occupy two sta- 

 tions in the north in a year, than to occupy six or eight, as I have done 

 when it was necessary, in order to get ahead of the other operations 

 of the survey. So much for the first section. 



" The second section is done, excepting the work of verification and 

 making necessary changes. There was a rich harvest of hydrog- 

 raphy in Long Island Sound, discoveries of detached rocks, about 

 which little had been said. But in the case of the entrance to New 

 York Harbor, there was a richer harvest; for there Capt. Gedney 

 found a new channel, now called by his name. This was either a new 

 channel, or a channel which has long existed, but which was newly dis- 

 covered ; most probably the latter, and that in the progress of the 

 hydrography of the coast survey. The advantages of a channel hav- 

 ing two feet more of water in it than the main ship-channel will be ap- 

 preciated by all. Buoys have been placed in it, and it is easy to find 

 the way out and in. 



" I was told last year that it was filling np ; which is not true. It 

 is often remarked, that the coast is changing every year, and there is, 

 therefore, little use of surveying it. The truth is, that there are a 

 few points in which the coast is really changing, and those points 

 should be carefully watched. We" should know where they are, and 

 why they are changing, and how to stop the changes if it is necessary, 

 and how to avail ourselves of them if it is necessary. But in New 

 York Harbor it was the easiest thing in the world, at a trifling cost, 

 to have the hydrography repeated, and the result showed that there 

 are not six inches more or less of water than there were when the 

 survey was made, so that the changes which have taken place in the 

 harbor, if any, are exceedingly slight. And if we consider the nature 

 of the operation of sounding, I should say that there had been probably 

 no change. 



" The discovery or determination of three channels in Delaware 

 Bay rewarded the exertions of the officers engaged there, Capt. Ged- 

 ney and Lieut. Davis. These channels are not of so much inter- 

 est as the channel into New York Harbor ; but they are of very 

 great importance. One of them is now constantly used by vessels 



