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. PROPOSED WORK. 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 sufficient, 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. ANNUAL WATER LEVELS OF THE NORTHERN AND NORTHWESTERN LAKES. 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. Stations. Sand Beach July. Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May. June. Feet. Fect. Feet Feet. Feet. Feet. Feet. Feet. Feet. Feet. Feel. 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, 2316 ESTIMATE. 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 channel,is finished the depth in many places will be more than double what it was orginally. The increased draft of the vessels 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 sus picion 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. It 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 lakes, will greatly facilitate this work, and will insure the maximum results with the minimum cost. In the field work of the resurvey of St. Marys River alone $36,239.15 can be economically and profitably expended during the fiscal year ending June 30, 1896. In addition, the new charts of the river must be drawn, engraved, and printed. At the same time other localities must not be neglected. New shoals should be resurveyed as promptly as discovered. New light-houses, buoys, landmarks, channel improvements, etc., must be located and marked upon existing charts. This work is accumulating, and it increases the longer it is postponed. In view of all these facts an estimate is submitted of $75,000 for "surveys and other expenses connected with the correcting and extending the charts of the Northern and Northwestern lakes, to be available until expended," in full confidence that the conditions actually existing amply warrant this expenditure. Estimate for the fiscal year ending June 30, 1896. For printing and issuing charts for use of navigators and electrotyping Total.... $3,000.00 75,000.00 78, 000, 00 Money statement. RESURVEY OF ST. MARYS RIVER. Allotted May 2, 1893, $20,000; February 17, 1894. $357.43. $20, 357.43 19, 704.86 July 1, 1894, balance unexpended July 1, 1894, outstanding liabilities 652.57 652.57 ...... Amount (estimated) required for completion of existing project. 36, 239. 15 36, 239. 15 Dates and amounts of appropriations for survey of Northern and Northwestern Lakes. Dates and amounts of appropriations for survey of Northern and Northwestern Lakes. Printing and issue of charts for use of navigators and electrotyping copper plate for chart printing: Dates and amounts of appropriations for survey of Northern and Northwestern Lakes. Abstract of bids for supplies for survey of Northern and Northwestern Lakes received and opened March 28, 1894, in accordance with advertisement dated March 8, 1894. No. Name and address of bidder. Supplies. Total. 1 2 7 212345OTI21231 P. M. Church & Co., Sault Ste. Marie, Mich P. C. Keliher, Sault Ste. Marie, Mich. 4 Peppard & McKinney, Sault Ste. Marie, Mich. Recommended for acceptance. REPORT OF LIEUT, CHARLES S. RICHÉ, CORPS OF ENGINEERS, UNITED STATES ENGINEER OFFICE, SIR: I have the honor to transmit the following report of operations of the survey of the Northern and Northwestern Lakes, resurvey of St. Marys River for the fiscal year ending June 30, 1894: At the beginning of the fiscal year a small field observatory had been erected at Sault Ste. Marie, Mich., observations for latitudes had been completed, and observations for longitude were in progress. The triangulation had been planned from Whitefish Bay to about 10 miles north of Lake Huron. Ten triangulation stations had been erected. The "Soo" base had been measured and computed. A line of precise levels had been run from Sault Ste. Marie, Mich., to Waiska Bay and the computations nearly completed. A limited amount of hydrographic work had been done and considerable progress had been made toward fitting out field parties for subsequent work. The allotment available for the fiscal year was $20,000, subsequently increased to $20,357.43. It was proposed to expend this amount in completing the essential astronomical work, in continuing the planning of the triangulation, in building stations, measuring angles, and in obtaining topography for the reach covered by chart No. 3 of the adopted series of new charts of the river. The hydrography it was proposed to take largely from the river and harbor surveys made and to be made in connection with the improvement of the river, such additional hydrography as might prove necessary for this chart being obtained by sounding through the ice during the winter. It was not proposed to duplicate recent Government surveys when doing so could be avoided. The results accomplished during the fiscal year are as follows: ASTRONOMICAL WORK. Observatory.-The "Soo Observatory" which was used for this work was built during the coldest part of the winter of 1892-'93. It forms an ell of the U. S. Engineer Office at Sault Ste. Marie, Mich., and is shown in ground plan in the accompanying drawing. Being on Government land, it was made more substantial in structure than would otherwise have been the case, as it can remain permanently and will be a useful point for comparisons of longitude, etc., for future surveys of the Engineer Department. The observing piers are of masonry capped with a 24 by 24 inch block of cut stone, and have proved very stable. A small masonry pier supports a 12 by 12 inch timber to which the astronomical clock is bolted, and a small concrete pier for holding a dish of mercury to act as an artifical horizon in azimuth observations, etc., stands to the north of the west observing pier. The foundations of all these piers are independent of each other, and of the foundation of the building. Latitude.-Observations for latitude were made on four nights, June 11, 14, 19, and 26, 1893. The manner of making them and their reduction is given in the report of Mr. Thomas Russell, appended, marked A, and attention is invited thereto for details. The resulting latitude of the east pier is 46° 30′ 06.25" north, which, reduced to the west pier, gives 46° 30′ 05.27′′±0.08′′ as the latitude used in the reduction of the triangulation. Longitude.-Observations for the difference of longitude between Sault Ste. Marie, Mich., and Ann Arbor, Mich., were made on ten nights, July 10, 15, 19, 20, and 26, and August 6, 7, 8, 9, and 12, 1893. On the first five nights Prof. Asaph Hall, jr., director of the Detroit Observatory at Ann Arbor, Mich., observed there, and I observed at the Soo Observatory. On the last five nights Prof. Hall observed at Sault Ste. Marie and I observed at Ann Arbor. The manner of making the observations and their reduction is also given in the report of Mr. Thomas Russell, appended, marked A, and attention is invited there to for details. At first considerable difficulty was experienced, owing mainly to trouble with the electro-magnets in the Ann Arbor Observatory. Fifty-ohm relays were used at the start, and while they worked satisfactorily at Sault Ste. Marie they did not do so at Ann Arbor, and had to be differently adjusted for receiving and sending signals. As it was desirable to avoid such changes in adjustment, more powerful relays were employed, with satisfactory results. The scheme of wiring in the Soo Observatory is shown on the accompanying drawing. The operating switches there shown are for the purpose of passing almost instantly from the connections required for observing and talking to those for sending or receiving signals. The four "two-point" switches in each group were securely fastened side by side and their levers were connected by a bar in such manner that by pushing the bar all four switches would move simultaneously. The necessary changes could thus be made so rapidly that the deisred number of signals could be exchanged well within the short time generally available for the purpose, and the astronomical work could be conducted with more deliberation than would otherwise have been possible. In this scheme of wiring the clock is kept on an independent 1-cell circuit, to avoid injury to its delicate break-circuit mechanism. The chronograph is also operated on a local circuit, in order that it may have a constant electric current through its magnet, to obviate as far as possible the necessity for changing the adjustment of the pen armature. An inspection of the drawing will show that when the 150-ohm signal relay is thrown out of this local circuit into the main line, the 150-ohm talking relay is thrown into the local in order to keep its current constant and avoid changes in adjustment of the chronograph pen armature. For this reason the two relays named should have practically the same electrical resistance, or else, by means of a rheostat, or otherwise, additional resistance should be put in the circuit where necessary to balance. A lightning arrester (not shown on drawing) is inserted in the main line where it enters the observatory. The scheme of wiring at Ann Arbor was substantially similar to the above, with the addition that a rheostat and galvanometer were inserted in the main line, with |