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Detroit, Mich., July 10, 1894.

SIR: I have the honor to transmit herewith, in duplicate, my annual report on the "Issue of the published charts of the Northern and Northwestern Lakes and surveys made for the purpose of keeping these charts up to date," for the fiscal year ending June 30, 1894.

Very respectfully, your obedient servant,

O. M. POE,

Colonel, Corps of Engineers, Bvt. Brig. Gen., U. S. Army.


Chief of Engineers, U. S. A.



The sundry civil act of March 3, 1893, appropriated the following amounts for the fiscal year ending June 30, 1894:

Survey of Northern and Northwestern Lakes.-For printing and issuing charts for use of navigators and electrotyping plates for chart printing, two thousand dollars. For surveys, additions to, and correcting engraved plates, twenty-five thousand dollars.

Under the first item the issuing of charts has been done in Detroit, Mich., from this office, the rest of the work required being attended to by the office of the Chief of Engineers, in Washington. During the fiscal year nearly all charts have been sold at the uniform price of 20 cents each. A few special lithographic charts have been sold for 10 and 5 cents each, and some charts have been issued free of charge for the official use of Government agents applying for them.


The following table shows the extent of this business:

Issue of the charts of the Northern and Northwestern Lakes during the fiscal year ending

June 30, 1894.

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The sum of $911.15 was turned into the Treasury from sale of charts. Total number of charts distributed to July 1, 1893. Distributed, etc., during fiscal year

Total distributed to July 1, 1894.

194, 399


199, 330

Under the second item of the above appropriation a number of charts have had corrections and additions made upon them in this office, and have been forwarded to Washington in order that the necessary changes might be made upon the engraved plates.

The following charts have been amended in this office:

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The information embodied in the above charts was derived from the best available sources of information. This work has been seriously impeded by lack of sufficient funds. The work is essential, however, if the charts are to be used for navigating the lakes.

The following progress on the combined chart of Lake Superior, scale 1:400,000, has been made: Completed 845 miles of inshore and offshore hydrography and 800 miles of shore line with the adjoining topography 3 to 5 miles back from shore, taking in the latest topographical and geographical information. The hydrography commences at Pigeon River, United States boundary line, and extends around the northwest coast and along the south shore to Pictured Rocks. The topography commences at Carltons Peak, on northwest shore and extends from this point to Pictured Rocks. The topography on the eastern end of Lake Superior and on both sides of St. Marys River, extending from Point Iroquois and Gros Cap to Little Rapids, has been reduced from resurvey, St. Marys River, 1893, and inked in.

Extensive alterations are being made to chart No. 1, St. Marys River, showing section 1 of the 20 and 21 foot Channel and the Hay Lake improvement. For this purpose the chart is being extended so as to take in Middle Neebish. The head of Collingwood Channel is alse to be added to this chart. The cities of Sault Ste. Marie, Mich., and Ontario are to be reduced from the field sheets of the resurvey of St. Marys River, 1893. The alterations in this chart are very nearly com pleted.

Mr. Edward Molitor has had charge of this work, and when not engaged on other work has devoted his whole time to it, with his wellknown intelligence and skill.


The increase in the draft of vessels navigating the Great Lakes and their connecting waters has rendered the resurvey of certain localities necessary. A large number of artificial changes have been made in the channels and harbors, and data obtained fifty years ago in the narrow or rocky parts of the waterway is not sufficiently accurate for a navigation twice the depth of that at the time these surveys were made. In conformity with the general plan of resurveying certain localities, a resurvey of St. Marys River was commenced in May, 1892, at an estimated cost of $64,080. Work was suspended on June 30, 1892, on account of the exhaustion of funds available. Four thousand dollars was allotted for fiscal year ending June 30, 1893, and $20,357.43 for fiscal year ending June 30, 1894. Work was resumed in January, 1893, and has been continued to date.

On June 30, 1893, a field observatory had been constructed at Sault Ste. Marie, Mich., on land belonging to the United States. The astronomical instruments and electrical apparatus necessary for the determination of latitude and longitude had been placed in position.

The observations for a fundamental determination of latitude had been made; eight primary stations definitely and four approximately located; a base line had been measured and the computations made; a line of precise levels had been run from Sault Ste. Marie to Bay Mills, Mich., and the computations nearly completed.

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Astronomical work. The computations for the latitude of the east pier of the observatory at Sault Ste. Marie were made. Latitude of east pier, 46° 30' 06.25" north. Reduced to west pier, 46° 30′ 06.27" ± 0.08"; the latter latitude was used in the reduction of the triangulation. Observations for the difference in longitude between the west pier, Sault Ste. Marie Observatory, and Ann Arbor (meridian circle) were made and the computations completed. Sault Ste. Marie Observatory (west pier) west of Ann Arbor (meridian circle) 2 minutes 27.995 seconds 0.036 second. Taking the best obtainable data for the longitude of Ann Arbor, 5 hours 34 minutes 55.25 seconds west from Greenwich, we have Sault Ste. Marie Observatory (west pier) west from Greenwich 5 hours 37 minutes 23.25 seconds or 84° 20′ 48.75". This value was used in the reduction of the triangularion. Observations and computations for the azimuth of the line Sault Ste. Marie Observatory to azimuth were made. Azimuth, 178° 06′ 38.87". This value was used in the reduction of the triangulation.

Continuous latitude and azimuth.-For the purpose of obtaining additional data in regard to the recently-discovered movement of the pole,

an effort will be made to observe latitude and azimuth continuously for a few years. A table of latitude stars has been very carefully prepared for this work, and a programme has been determined upon for the azimuth observations. Assistant Engineers Ripley and Dixon, who are employed upon the river and harbor works in the vicinity, have volunteered for this work, but so far have been too busy to accomplish very much.

Triangulation.-A plan of triangulation connecting the triangulation of Lake Superior with that of the Straits of Mackinac was devised, but some reconnoitering is necessary to ascertain whether this plan or any other is practicable in order to make a complete connection between the two systems named above.

Eighteen primary and 12 secondary stations were built and the necessary lines of sight cut. The angles at 11 stations were measured; 20 measures each for 91 primary angles, and 8 measures each for 67 secondary angles were made.

In this work a direct connection was made with the river improvement tertiary triangulation at Stations Iroquois and South Gros Cap. Topographical work.-In order to obtain the requisite topography for chart No. 3 of the adopted series of the new charts of the river in one season, two small topographical parties were placed in the field. These parties started at the lower end of the reach (just east of Sault Ste. Marie, Mich, and Ontario) and worked westward. On the American side, 51.4 square miles of territory were covered, and on the Canadian side 40 square miles. The average cost was about $60 per square mile. The survey shows all the features of the ground, 20-foot contours, land survey lines, etc.

Hydrography.-In connection with the operations of improving the ship channel 20 and 21 feet in depth between Chicago, Duluth, and Buffalo, a hydrographic survey of a large portion of the river adjacent to the localities where improvements are in progress, or are contemplated, has been begun. This survey will cover the reaches of the river shown on charts 2 and 3 of the adopted series of new charts. As this work, like all the "river and harbor" surveys, will be done with great care and accuracy, the lake survey will not duplicate it, and the soundings obtained will be used for the new charts.

Office work. In addition to the computations for latitude, longitude, and azimuth, an adjustment of the completed triangulation was made, the geodetic coordinates of the various stations in the primary work and of the tertiary stations in the river improvement triangulation were made.


The work already done will enable chart No. 3 of the new series to be issued when the hydrography shall have been completed. The next allotment will be expended in extending the triangulation, and, if suffi cient, in obtaining enough information to permit the publication of chart No. 2. This will require the topographical and hydrographical work to be carried down the river from Sault Ste. Marie. It would be very desirable to have some accurate magnetic observations made during the progress of the survey, and it is thought that this can be done at small cost. Everything is now in readiness to push the work as fast as the necessary funds become available.

The resurvey of St. Marys River has been under the local charge of First Lieut. Charles S. Riché, Corps of Engineers, U. S. Army, assisted by Assistant Engineers Morley, Haskell, Von Schon, Molitor, and Balch, and Mr. Thomas Russell. In Lieut. Riché's report and the sub

reports attached thereto can be found all the details connected with the prosecution of the work.


Daily observations were made under my direction at Sand Beach, Mich., on Lake Huron, and at the head of St. Marys Falls Canal, Sault Ste. Marie, Mich.

The following table embodies the results:

Monthly mean of water levels for the following-named stations below the planes of reference adopted in 1876.


Sand Beach
Sault Ste. Marie

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July. Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May. June.

Feet. Feet. Feet. Feet. Feet. Feet. Feet. Feet. Feet. Feet. Feet Feet. 3.50 3.64 3.93 4.14 4.37 4.57 4.62 4.61 4.46 4.23 3.83 3.53 2.808 2.724 2. 854 2.913 2. 968 3. 504 3.725 3. 809 3.919 3.528 2.556 2.316


The resurvey of St. Marys River is now in progress and the work is being pushed as rapidly as available funds will permit. The traffic through the river is already so great, that the publication of new charts is becoming more and more essential every day. These charts would show to the navigator the new channels upon which the Government has been expending so much money, together with all ranges and landmarks along the shores. They would show the best courses for his vessel to run and the dangers to be avoided in the difficult navigation of this portion of one of the great commercial waterways of the world.

Throughout the lake region larger and larger vessels are being built each season. Their value to the general public is increasing every year, and nothing should be left undone in efforts looking toward the safety of these,costly vessels and their cargoes.

The connecting channels of the lakes are now from 4 to 5 feet deeper than they were when the original surveys were made, and a still further increase in depth of 4 feet is approaching completion. When the new 20 and 21-foot finished the depth in many places will be more than double what it was orginally. The increased draft of the ves sels using these channels, combined with the low water of recent years, has caused the larger and more expensive vessels to discover dangers previously unsuspected, and to discover them by the costly process of striking them. All dangers so discovered should at once be surveyed and located upon the charts in order to prevent the repetition of similar accidents at the same point. Localities deemed perfectly safe for navigation when smaller vessels were used are now regarded with suspicion by the larger vessels, and it is essential that certain special areas be reexamined.

Accurate knowledge of dangerous obstructions can be obtained in but one way, and that is from charts. When the Government sells charts to navigators these charts should embody the latest and most accurate information concerning the localities to which they refer. is essential, therefore, that all the charts be kept constantly up to date. The organized districts, in connection with the river and harbor work of the Corps of Engineers now established at the chief cities on the


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