determined. Having these data, we then know from computation the latitude and the longitude of any point, and the angle with the meridian of any line connected with the triangulation. This is the second part of the work.

We have thus a great scheme in which the progress may be very rapid, because the steps may be very great. You may have,— as we have in some cases in our New England triangles, — a side of 60, 90, or even 100 miles in extent; and thus you may make vast strides along the coast at once, by taking advantage of hills properly situated in the interior of the country and overlooking the ocean shore.

Having determined these points with great nicety, with large instruments, and much care, the work between them need not be done so elaborately. New points are determined between the former upon the same great system of triangulations, called the secondary triangulations. Upon this, with a still less exact mode of work. ing — namely, with the plane table the topography is laid down so far as it may be necessary, to show the coast to the navigator, and for purposes of defence. All the points are checked by the secondary triangulations, which in their turn are checked by the primary; so that having taken great pains in the first part of the work, you cannot wander far out of the way in the second part of the work, or in the topography.

Having thus determined the outline of the coast, the hydrography gives you a picture of the bottom of the sea, just such as the topography gives you of the land above its surface; and this completes the

survey.

Now these triangulations, the astronomical measurements, and the topography, had been carried, at the time that I took charge of the survey, into Narragansett Bay, on the one side, and into the Chesapeake Bay upon the other. It was a plain thing, then, for me to go on with the triangulation to the eastward, and to carry on the work to the southward, thus burning the candle, as it were, at both ends. I preferred, however, to divide it into parts and set other portions to burning also. Estimating, as well as I could, from the best means to which we had access, the shore line of the coast - by which I mean to include all the indentations, estuaries, rivers up to the head of tide water, and harbors - I endeavored to divide the coast into as many sections as I thought the means I should be likely to obtain would allow me to commence the survey in.

The question was asked me about this time, how long I thought the

survey would be in finishing. This was at the session at which Texas was annexed; and I asked the gentleman what extent of coast he meant to include? Did he mean to the St. Mary's? Did he mean to include Florida and Louisiana, which had been purchased after the survey had been commenced? Did he mean to include this coast of Texas, which we had just been adding to the Union, and which alone had added two years to the duration of the survey? Since then Oregon has been made a territory, and California acquired, and thus the limits of our coast have been greatly extended, and with this extension the importance of the survey has greatly increased.

Originally, to return to my statement, I divided the survey into eight sections. Texas made a ninth section. Oregon makes a tenth. Now I will show you, as well as our time will permit, how far we have progressed in the several sections; I have had these diagrams colored, so that you can almost see for yourselves the whole extent of the work.

[Prof. B. then proceeded to explain from the diagrams the progress of the work.]

In the first section, from Point Judith to the boundary, we have now finished the primary triangulations, from the base on the Boston and Providence Railroad, along the coast of Rhode Island, Massachusetts, New Hampshire, into Maine. The point which I expect in a few days to occupy, is in the neighborhood of Portland. Now it would be very easy for me to calculate how long it would take me to extend these primary triangulations to the boundary; because I have the statistics of this part of the work; I know how long it has taken me to do a similar amount of this work. But my object is not to carry the operations at once to the boundary, in the shortest space of time, because I am already in advance of the secondary triangulations. This is a part of the coast where the primary triangulation may be carried on rapidly. The hills of New England, as Mr. Hassler said, seem as if they had been made for triangulation. They are so situated that we can pass rapidly along the coast with long strides; and the only difficulty is to avoid being tempted to make the lines too long. I have frequently, however, in taking such long lines, taken also an intermediate shorter line, for the purpose of verification. We have then passed, in five years, on the primary triangulation, from Rhode Island to Maine; and it could have been done in three years, had it been desirable so to occupy the time. But being so far in advance, I am enabled to occupy a portion of the season at the

South, in the Autumn and in the Spring, and thus not to confine the field of my personal labors to one section, but to spread it over many sections, and particularly to establish the bases upon which the triangulations in the different sections rest.

The secondary triangulation has extended along the shore, determining the positions of points near the coast, around the peninsula of Cape Cod to Cape Ann. There are now two parties at work upon this step in the process; one passing from Cape Ann to Newburyport and the other from Newburyport to Portsmouth; so that by the end of the season, we shall have reached nearly to Saco, in Maine, with our secondary triangulation.

But

The topography has been carried regularly forward in the same way, with but one exception, in which I have perhaps taken some responsibility. I certainly did have Boston Harbor surveyed two years before it would have been done in the regular course. then I had a very violent motive for this; namely, an appropriation made by the State of Massachusetts to hasten the survey of the coast; an act of liberality which has never been imitated by any other State in the Union. We have two large manuscript maps of Boston Harbor, which you will see in the State House, in the month of October next, of a very finished character.

Thus, in six years, (adding the present year,) at this end of the work, we have advanced from Point Judith, with the primary triangulation, to Portland, with the secondary beyond Portsmouth, and with the topography to Gloucester.

The hydrographers have had a long and difficult piece of work in this section. They have had those famous Nantucket Shoals to stop them. But if the Survey had rendered no other benefit to the country than making known the before unknown and hidden dangers of that part of the coast dangers, because unknown and hidden — it certainly would have repaid to the country in money the whole amount which it has cost. One vessel which came very near stranding upon shoals now, through the enterprise of Lieut. Com'g Charles H. Davis, made known and familiar to us had a cargo which paid the Government a duty of $125,000; and if this sum had been devoted to the survey, the shoal would have been discovered years ago. I have endeavored to mark upon this map the discoveries which Lieut. Davis has made. They consist of an important shoal outside of the Old South Shoal of Nantucket, lying directly in the track of vessels from New York to Europe and returning, and of vessels

passing from the New England States to the Southern States, and South America. The dangers which he has developed, and six of which, he made known last year, have, for all time, enrolled his name among the benefactors of his race.

The hydrography has been extended up Buzzard's Bay, through Nantucket Sound, and through the Vineyard Sound; it has embraced the Nantucket Shoals, and has included the hydrography of Boston Harbor, an accurate chart of which has been made.

The results of the survey pass through a regular process, from the time the observations are made in the field, to the time the map is produced in the office. The assistants, who make the observations, report them and compute them. Other computers also pass over the same calculations. The results are brought into juxtaposition and compared. If they agree, they are considered as correct. If they disagree, the cause is carefully examined and the error corrected. The results, thus verified, are placed upon paper in the ordinary forms of projection of maps. They are next engraved, as fast as we can find hands 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 citizens, 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. The force of computers requires to be increased; the force of draughtsmen and of engravers requires to be increased. It is a remarkable fact, such is the prosperity of this branch of art, and such the demand for engraving in common life, that it is almost impossible to get a good map-engraver to leave his home for any inducement I can offer him, to come to Washington and place himself there under our direction in the office. attempts to procure work by contract, out of doors, in a finished style and with exactitude, have been, in some instances, partially successful. It was a source of complaint that Mr. Hassler sent abroad for engravers. Now I know that they cannot be had at home. When we wanted to increase the force of our engravers, we could not tempt, by any reasonable emolument, such engravers as we wanted to engage in the service of the government. The reply was a natural one, and one which I could not meet by argument: -"I am

Our

at home here; my family relations are all here; I do not wish to change them; I have as much to do as I can attend to; and I can earn just as much as I need, and therefore do not wish to leave my home nor to make any engagement with the government."

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 occupied in two years and a half, at the present rate, making the astronomical 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 stations 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 opera. tions 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 hydrography 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 still; for there Captain Gedney found a new channel, now called by his name. This was either a new channel, or a channel which had long existed, but was newly discovered, most probably the latter, and that in the progress of the hydrography of the Coast Survey. The advantages of a channel, having two feet more of water in it than the main ship channel, will be appreciated by all. Buoys have been placed in it, and it is easy to find the way out and in.

It was reported last year that it was filling up; which, in passing, be it said, is not true. It is often remarked that the coast is changing every year, and that there is, therefore, little use in 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; 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 of water, more or less, 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, considering the nature of the operations of sounding, I should say that there had been probably no change. The discovery remains valid to this day the goodness of the channel unimpaired.