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 $3,000.00 75,000.00 Total.. Money statement. RESURVEY OF ST. MARYS RIVER. Allotted May 2, 1893, $20,000; February 17, 1894. $357.43.. 78, 000, 00 $20,357.43 19, 704.86 652.57 652.57 Amount (estimated) required for completion of existing project............. Amount that can be profitably expended in fiscal year ending June 30, 1896..... 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. Surveys and additions to and correcting engraved plates: March 2, 1889. August 30, 1890 March 3, 1891. March 3, 1893. Total. $5, COO 10,000 10,000 5,000 25,000 55,000 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. 12123-DOTI22231 Groceries ..do 4 5 P. C. Keliher, Sault Ste. Marie, Mich .do ..do .do ...do ..do 5 1 Peppard & McKinney, Sault Ste. Marie, Mich. .....do ..do .do ..do Meats .do Lumber. * Recommended for acceptance. † 504.53 † 540.25 * 635.00 *665.00 * 120.00 150.00 200.00 *391.31 Incomplete. No bid on milk. 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. Maric, 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 crected. 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 cast pier is 46° 30′ 06.25" north, which, reduced to the west pier, gives 16° 30′ 05.27′′±0.03′′ 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. Åsaph 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. Mario 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 ance. a view to keeping a constant current therein by plugging and unplugging resistThe fluctuations in strength of the main-line current were found so sudden and irregular in the length of line used, that more trouble was caused by trying to work this arrangement than by leaving it alone. After the first few nights, therefore, no attention was paid to this feature of the subject. With specially devised apparatus for steadily altering its resistance, there is no doubt that the current in the main line can be kept practically constant and the galvanometer needle kept at a steady pointing in much the same manner as a boat is held on a fixed course, but I doubt very much if the accuracy of the work would be materially increased thereby. In this work Assistant Engineer F. C. Shenehon acted as recorder at the Soo Observatory and Mr. Elmer L. Allor at Ann Arbor. The services of both were highly satisfactory. I am especially indebted to Inspector L. Fleming, who, without extra compensation, performed the duties of telegraph operator at Sault Ste. Marie during the longitude work, in addition to his regular duties in connection with the river and harbor work in this vicinity. Mr. Fleming also took charge of the chronograph and obtained first-class results from the old-style instrument that was used in this work. The reduction of the Ann Arbor work gives Soo Observatory (west pier) west of Ann Arbor (Meridian Circle) 2 minutes 27.995 seconds 0.036 seconds. Taking the best obtainable value for the longitude of Ann Arbor, 5 hours 34 minutes 55.25 seconds west from Greenwich, gives Soo Observatory (west pier) west from Greenwich, 5 hours 37 minutes 23.25 seconds, or 84° 20′ 48.75", which value was used in the reduction of the triangulation. In September, 1893, an attempt was made to determine the difference in longitude between the Soo Observatory and the new Naval Observatory at Washington, Prof. Hall, who was temporarily visiting Washington at the time, making the observations there. The observations were very incomplete, owing to cloudy weather, and no least square reduction of them was made. My thanks are especially due to Prof. Asaph Hall, jr., for valuable suggestions and assistance throughout all of the longitude work and also to the Western Union Telegraph Company for granting us the use of their wires without charge. Azimuth.-A triangulation station, known as A azimuth, having been located in Canada nearly north of the observatory for the purpose of forming a mark for the azimuth observations, it was determined to observe azimuth from the west pier of the observatory. These observations were delayed owing to repeated interference with the mark by certain mischievous persons who resided near it. Two “light boxes" that had been erected at the station were removed and secreted. When the third one was put in place, Mr. Joseph Cozens, Ontario land surveyor, very kindly lent us his assistance, and put up a sign notifying the public that the box was an Ontario land survey mark and that he would prosecute any parties who disturbed it. For ten days and nights thereafter the station was watched, but no further mischief was attempted. The Canadian authorities at Sault Ste. Marie, Ont., gave us every assistance in their power, and it is sincerely trusted that the mark will not again be disturbed. The observations for azimuth were made on four nights, March 2, 8, 14, and 19, 1894, by Assistant Engineer E. E. Haskell. The manner of making them, and their reduction, is also given in the report of Mr. Thomas Russell, appended, marked A, and attention is invited thereto for details. The resulting azimuth of the line Soo Observatory (west pier) to A azimuth is 178° 06′ 38.87" from the south through the west, which 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. A short discussion of this subject, together with the adopted star lists, will be found in Mr. Russell's report (A). An effort will be made to have the places of these stars observed at one or more fixed observatories during the progress of the work. PLANNING TRIANGULATION. At the beginning of the fiscal year Assistant Engineer Fred Morley was engaged in planning the triangulation. He continued this work until November 15, 1893, when he left for Ann Arbor to resume his duties at the University of Michigan. During his season's work Mr. Morley made a complete plan of the primary triangu lation from the old lake-survey line Michipicoten-Gargantua to the old lake survey "Mackinac Base." In addition, Mr. Morley planned a secondary system of triangulation for Whitefish and adjacent bays. Mr. Morley's final report of this work is appended, marked B, and attention is invited thereto for details. Mr. Morley's plan contained a large number of lines over 20 miles in length, the measurement of whose direction would have involved the extensive use of heliotropers. This would have made the angle-measuring expensive, as the experience we have already had with such lines has shown that they are liable to cause vexatious delays to the angle-measuring parties. I considered it advisable, therefore, to reduce the number of such lines as much as possible, and the large amount of information obtained by Mr. Morley rendered this a comparatively easy matter, involving but a small amount of additional reconnoitering. Mr. Morley's connection with old station Gargantua was through Canadian territory back of A Mamainse. This country is an absolute wilderness, and while Mr. Morley's plan of triangulation is doubtless the best that could be obtained through this back country, the measurement of the angles would be expensive, and it was thought best to see, by some additional reconnoitering, whether a cheaper connection could not be made with the old line Mamainse-Gargantua from some station on the Michigan shore of Lake Superior. A hill 260 feet above the lake was found at Crisps Point, Michigan, where, by erecting a high station, and by waiting until the refraction is excessive, A Gargantua, 431 feet above the lake and about 60 miles distant, would be visible. All things considered this connection would be more economical than the other, in addition to giving better angles, and it has therefore been adopted. It is probable that Caribou Island Light-House can be located at little or no cost from the three stations shown on the drawing herewith, by reading the direction of the light from each of these stations at night when refraction is at its greatest. It is important to locate this island, as its location has never, to my knowledge, been accurately made. The additional reconnoitering necessary for the modification of Mr. Morley's plan was done by Assistant Engineer E. E. Haskell in accordance with my instructions. Mr. Haskell's report on this work is appended, marked (, and attention is invited thereto for details. Mr. Haskell also selected some secondary stations to connect the lower end of the river improvement tertiary triangulation with the primary system. These stations, together with the adopted plan of the primary triangulation, are shown on the drawing submitted herewith. Although the number of lines requiring the use of heliotropes has been greatly reduced, some such lines still remain. These are mostly at the northern end of the work and are necessitated by the length of the old line Gargantua-Mamainse, to which connection must be made. It has been considered advisable to measure a base line on Batchewana Island, as the nearest bases to this end of the work, excepting the short Soo base, are at Keweenaw Point and the Straits of Mackinac. Batchewana Island being about halfway between the two, would make a very valuable point for a good base line. The Soo base would then serve as a check base for the work closer to the river; it is too short properly to control the long lines between the old stations of the lake survey at the cast end of Lake Superior. Mr. Morley's plan of secondary triangulation in Whitefish and adjacent bays involved the occupation with an instrument of each of a large number of secondary points. The primary points in this locality look down upon these bays in such manner that it would be possible to locate all necessary secondary points by intersection from at least three primaries, and with lines not exceeding 20 miles in length, without occupying any of the secondary points with an instrument. I can see no reason why this method should not give as accurate, and in many cases more accurate, results than the other, and the cost of locating the secondaries would be but little more than that for maintaining targets at each of them for the necessary length of time. These points could probably all be read in during the otherwise "dead time" that the angle-measuring parties were waiting for favorable conditions for reading the long primary lines that involved the use of heliotropes. In fact, I see no reason why this method of locating secondary points for hydrographers and topographers by intersection from a few primary stations should not generally be used more extensively than it appears to be. All secondary points on the resurvey of St. Marys River will be located in this manner as far as practicable. BUILDING STATIONS. Assistant Engineer Glen E. Balch was engaged in building stations at the beginning of the fiscal year, and continued this work until the middle of October, 1893, when it was stopped for the season. By this time 18 primary and 12 secondary stations had been erected and the necessary lines cut. Subsequently, Mr. Balch took charge of the erection of a higher station at South Gros Cap, which was needed to permit A Larke to be seen therefrom. During the last few days of June, 1894, Mr. Balch was engaged in erecting A Pennefather, one of the new stations required by the modified plan of triangulation. Mr. Balch's report is appended, marked D, and attention is invited thereto for details. The recent eight-hour law has increased the cost of this work to the Government. |