The discharges were computed for each section as before, with the following results: Section 1. Discharge, 599.9 cubic feet per second. The mean of these 598.6 cubic feet=22.17 cubic yards. = The mean of all the soundings, corresponding to water height of — 2.02 =9.3 feet. Average width=165 feet. Cross-section=1,534.5 feet. Mean of all velocities observed=0.39 foot per second. The tables of the water-gauge and current observations show that greater velocities and more frequent changes of direction were observed at the canal than at the entry, and, in both cases, that the velocity of the currents running in was greater than of those running out, which seems to be due to the fact that the lake rises in less time than it falls. From the tables it will be seen that, on July 27, the water in the lake at 12 m. was 2.02; at 1 p. m. it had risen to 1.85; at 2 had fallen to 1.96; at 3 to 2.00; and at 4 to 2.01-requiring three hours to fall where it had risen in one. On July 31, at 2 p. m., the water was 2.01; rose to 1.68 at 3; fell to 1.78 at 4; stood at 1.73 at 5, and 2.04 at 6; a rise of 0.33 in one hour, falling afterward 0.36 in three hours. But the changes are too frequent for hourly observations to show this as fully as those taken every fifteen minutes; so, on August 9, from 10.15 to 10.45 a. m., the lake rose from 2.53 to 1.98=0.55; producing an inward current of 5.7 feet per second; after which slight oscillations occur, the water gradually sinking, until at 12 m. it was 2.43, there having been, in the mean time, four outward currents observed, the greatest velocity being 2.66 feet per second. Again, from 4 to 4.15 p. m., it rose 0.42, and at 5.30 had fallen to the former level. These examples have been selected at random from the tables, and though there are many contradictions, the rule seems established. And this difference between the inward and outward currents is really greater than shown in the tables, for at both the entry and canal the observations were made near the inner or bay end. For instance, a rise of water in the lake would produce a flow through the canal, the greatest velocity being at the lake end, where the fall would be greatest, and observations taken at the time, at the bay end, would give the smallest actual velocity. But when the lake falls, the water rushing out from the bay, observed at that end, would give the greatest velocity, and this difference enters all the preceding computations concerning the discharge, since the same cross-section was necessarily taken. The difference would also be heightened at the entry, at least, though perhaps to an extent hardly noticeable, by the water from the rivers flowing on the surface, since it is so much warmer than the water of the lake. Respectfully submitted. Major D. C. HOUSTON, Corps of Engineers, U. S. A. JOHN PIERPONT, Assistant United States Engineer. Report of W. H. Newton, civil engineer. To Gen. W. W. BELKNAP, Secretary of War, Washington, D. C.: I have the honor to transmit to you herewith a detailed report of the survey and examination of Superior Harbor, and its connections with Lake Superior, made in compliance with his excellency's letter of instructions of May 25, and letter of the Hon. Secretary of War, of May 31, appointing Col. D. C. Houston, of the United States Engineers, to act conjointly in the survey and examination, directing an examination to carefully and fully determine, by actual survey, the facts pertaining to the following questions: 1st. Has the surface of the water in the Bay of Superior been lowered permanently since the opening of the canal across Minnesota Point? 2d. Has there been any change in the bottom of the bay, or through the channel-entry into the lake, since the opening of the canal? 3d. That careful measurements and soundings on the outer or lake side of Minnesota Point be made, and the same so plotted and laid down as to show any change in the position of the shore, or depth of water, since the soundings were made by the United States survey heretofore; and also to show the change of the portion of the bar at the entry since the opening of the canal. By appointment, I met Colonel Houston at Chicago, June 12, for consultation, where a detailed course was determined upon for prosecuting the work. Colonel Houston's official duties, in connection with his charge of harbor improvements, he informed me, would preclude his personal supervision of the work. I arrived at Superior June 24, and verified the soundings at the mouth of the Saint Louis River, previously taken by Colonel Houston's subordinates. On the 28th of June Mr. John Pierpont, assistant engineer, arrived at Superior, under instructions from Colonel Houston, to make the surveys and examinations determined upon, under my personal supervision. The hydrography has been executed with accuracy and detail from the shore. Lines of soundings, connected by triangulation with lake-survey base-line on Minnesota Point, were projected, each 500 feet, through the Bay of Superior and on the lake side of Minnesota Point from the mouth of the Saint Louis River to the Du Luth breakwater, and each 45 feet, through the mouth of the Saint Louis River and Du Luth Canal. Depths under 20 feet were measured by sounding-pole; more than that depth, by sounding-line, giving the contour of the bottom. Tidal observations (hourly) were taken through one lunation, at tidewater gauges, located on the west side of the Du Luth break water, at the Du Luth grain-elevator, (both in the lake;) at wharf north of the Du Luth Canal, in the bay; on north and south sides of the Du Luth dike, about 1,300 feet from Rice's Point; in the Bay of Saint Louis, on the north side of railroad-dock, on Rice's Point; at Quebec pier, in the Bay of Superior, in Superior; at the foot of Second street, Superior; on the north bank of the Nemadji River, and on Minnesota pier; at the mouth of the Saint Louis River, outside of shore-line of Minnesota Point. Accurate levels were taken by Mr. Pierpont, referring the zeros of all the tide-gauges to a bench established in 1861 in the Bay of Superior, near Quebec pier, by officers of the lake survey, a record of which was furnished by Gen. C. B. Comstock, superintendent of United States lake survey, thus connecting them with the planes of reference, the high water of 1838, as established by Capt. G. G. Meade, superintendent of the United States lake survey, as shown by his report accompanying Chief of Engineer's report for 1860, pages 7 and 8, and as per letter of Gen. C. B. Comstock, under date of June 29, 1872, from United States lake-survey office, Detroit, which says: "Plane of the zero of gauge at Superior City in 1861, 0.20 foot above the six-inch spike driven into the post 1.44 above main sill at the northwest corner of Johnson & Alexander's mill. The zero of gauge was + 2.27 above high water of 1838." From this official record all observations at the water-gauges during the survey and soundings taken on the bay and lake were reduced and report completed. On the 16th of November I received the following letter from Col. D. C. Houston, changing the record of the zero of the lake-survey gauge at Superior: CHICAGO, November 14, 1872. SIR: I was in Detroit yesterday, and made an examination of the records of the lake survey, for the purpose of settling, as far as possible, the discrepancies in our information. It appears that, from 1859 to 1863, inclusive, the readings of the gauge at Superior City were reduced on the assumption (arbitrary) that the zero of the gauge was 2.27 feet above high water of 1838. These reductions are found in the manuscript reports of superintendent of lake survey for 1864, which was not published. In 1870 the records were revised, and reduced on the assumption that the high water of 1838 was 2.85 feet below the zero of the gauge, and the table published in the report of the Chief of Engineers for 1870, of which you have a copy, is made on this assumption. The figures given in this table for the years 1859 to 1863 are 0.58 of a foot (mean) tess than those given in the report of the superintendent of the lake survey of 1864. D. C. HOUSTON, W. H. NEWTON, Esq., Madison, Wis. Maj. Engineers. * Thus, after several applications to the superintendent of lake survey for a correct record of observations made and results reported, we have the zero of this gauge finally established at + 2.85 feet above high water of 1838, and reduction of mean elevation of surface of water refers to this plane, and is found to be 1.954, while the first record given is referred to for the soundings of 1861 and during the survey. Accompanying map, A, of Bay of Superior and connections with the lake, shows the location of the gauges and the lines of soundings taken. From the 16th of July, at 7 a. m., to the 8th of August, at 6 p. m., hourly observations were taken at all the tide-water gauges; and from the 9th of August, at 6 a. m., to the 12th, at 6 p. m., observations were taken each fifteen minutes; from the 13th August, 7 a. m., to the 19th, 6 p. m., hourly observations were taken; and simultaneous observations were taken during the above periods of the velocity and direction of the currents of the mouth of the Saint Louis River, at the Du Luth Canal, and at the opening in the Du Luth dike, near Minnesota Point. Accompanying plat, B, by profile shows the changes of level of the surface of the water at the several gauges and their reference to the high water in 1838, changes of direction and velocity of the current at the mouth of the Saint Louis River, at the Du Luth Canal, at the easterly end of the Du Luth dike, through an opening under the railroad-track of 800 feet area, as per measurement made August 19; also, profile of Minnesota Point, on the lake-survey base-line from south side of the mouth of the Saint Louis River to the north side of the Du Luth Canal and Du Luth dike, from base-line on Minnesota Point to Rice's Point dock in Saint Louis Bay. Plane of reference, high water of 1838. Also, variations of barometer by profile, from observations furnished by Sergt. I. Dascomb, United States Signal Corps, stationed at Du Luth, with tables of barometrical observations corrected, and of daily amount of rain-fall from July 16 to August 19, inclusive. Table No. 1.-Shows daily mean elevation of water at the tide-water gauges, from July 16 to August 19, inclusive, and velocity, direction, and period of currents at mouth of Saint Louis River, at Du Luth Canal, and at opening in Du Luth dike, during this survey. Means refer to the zero of gauge as established by General Meade, 1861, and for compari son. Table No. 2.-Chief of Engineers' report, 1870, page 605, deduct 0.58 of a foot, to correspond with change made by lake survey in 1870. Table No. 2.-Means maxima and minima, from lake-survey tide-water gauge at Quebec pier, from July, 1859, to April, 1872, inclusive, and from tide-water gauge at the mouth of Saint Louis River, established by United States engineers in charge of harbor improvements, from May to December, 1871, inclusive, and from May to October, 1872, inclusive, record of which was furnished by Col. D. C. Houston, United States Engineers. Table No. 3.-Total variations of water-level at each station, from July 16 to August 19, 1872, inclusive, and differences of level between lake and bays of Superior and Saint Louis.* Table No. 4.-Observations for the Smithsonian Institution taken at Beaver Bay, Minnesota, from January 26 to October 30, 1859, inclusive, by Hon, Thomas Clark. Table No. 5.-Moon's meridian, transit, and phases at Superior, Wis., latitude 46° 30′ north, longitude 92° 25', Greenwich, and hour of high water at the gauges at the Du Luth elevator, Quebec pier, and Saint Louis Bay, from July 16 to August 19, 1872. Table No. 6.-The velocity, gauge, and discharge of Nemadji River, near its mouth, and the Saint Louis River, at Fond du Lac, during this survey. The first point of examination: Has the surface of the water in the Bay of Superior been permanently lowered since the opening of the Du Luth Canal across Minnesota Point? Referring to Table No. 1, the mean elevation of surface of water at Quebec pier for July and August, 1872, is 2.534; reduced, 1.954. Referring to Table No. 2, the mean for July and August at Quebec pier, from 1859 to 1872, inclusive, is found to be 1.649, showing the surface to be of a foot lower in 1872 than for thirteen years, which includes the unusually low water extending from 1862 to 1868. Again, referring to Table No. 2 for the years 1870 and 1871, for the months of July and August, the mean elevation of surface of water at Quebec pier is found to be 1.48, and in July and August, 1871, the mean elevation of water in the lake, at the mouth of the Saint Louis River, is found to be, by the reduction, 2.41, showing the surface of the bay to be 0.93 of a foot above the surface of the water in the lake in July and August, 1872. Again, referring to Table No. 2, lake-survey gauge reports, mean surface of water at Quebec pier, 2.29 in April, 1872, and United States engineer gauge report, mean for month of May at the mouth of Saint Louis River, 2.73, water at Quebec pier 0.44 of a foot above surface of water in lake, and every indication of a gradual rise in water in the lake during each month of that season. Again, referring to Table No. 1, the mean surface elevation of water, at all the points of observation by gauge in bay and lake, are practically *Table No. 3 is from computation of Colonel Houston, and varies slightly from my own, owing, doubtless, to error in my copy of observations. the same. Thus, by measurements made in this survey, a lowering of bay is shown as compared with mean for thirteen years of of a foot, and, as compared with the preceding year, of 0.93, and from April to May, 1872, of 0.44, and that the mean elevation of the surface of water in the lake is increasing, thus increasing the real difference by so much as it may have risen in each month, which is shown, by reference to Table No. 2, to average a rise of 22 of a foot per month from April to the period of the highest water each year; add this to the difference as found and there is found 1.15 of a foot lowering of the surface of water in the bay, which is confirmed by the fact of the breaking away of the Du Luth dike, on the 28th of April, 1872, which diverted the water to the Du Luth Canal, and resulted in lowering the water in the bay to the level of the lake, and evidently it has so remained up to the date of this survey. My attention has been directed to the marked difference between April and May, 1872, as indicating some error in re-establishing the zero of the gauge. The careful examination of the observer for the lake-survey gauge at Quebec pier, up to its removal to Du Luth by General Comstock, elicits no probability of error, and the letter of Captain A. M. Miller, of United States Engineers, to Colonel Houston, of November 11, 1872, confirms the re-establishment of this gauge after the fire of August 9, 1871, and its replacement on the succeeding day by marks that would avoid any appreciable error. The removal of this Quebec pier lake-survey gauge a few days prior to the order for this survey by General Comstock without verifying its reference to the bench established by General Meade in 1861, and the mistake of General Comstock of 0.58 of a foot in stating the record of the zero of the gauge of Quebec pier, to which the Chief of Engineers report, 1870, refers to which this survey referred to determine the question involved, with the lack of uniformity in the reductions made, in 1870, of the observations of the years preceding 1864, as compared with those reductions reported in 1864, have protracted the work of this examination, destroying perfect confidence in the reductions of 1870, and appear to have subordinated this survey and examinations to the convictions of the superintendent of lake survey of their unimportance, and hence semiofficial inaccuracies were not material; thus rendering the references to measurements made under my personal observation by Hon. Thomas Clark, civil engineer, prior to this examination, and at the exact period of the opening of the Du Luth Canal, pertinent, as corroborative of the results elicited by this survey. On the 29th of April, 1871, Mr. Clark, under my personal supervision, ran a series of cross-section levels over Minnesota Point, between the surface of the water in the Bay of Superior and the surface of the water in the lake, and by these measurements the lake level at the mouth of the Saint Louis River was found to be 0.83 feet below the level of the bay, and one mile from the mouth of the river it was found to be 0.90 feet; three miles from mouth of river, 1.08 feet; five miles from the mouth, 1.16; and by projection of the same plane of ascent at the Du Luth Canal, it was determined to be 1.19 feet. The day was calm and the ice was pushed up from five to twelve feet above the surface of the water in the lake, and grounded about 100 yards from Minnesota Point, with open passages through and under it, causing a perfectly calm surface between the ice and Minnesota Point, showing that, from April to May, 1871, there was a mean difference of level of water on the bay and lake of 1 foot; and Colonel D. C. Houston, in Senate Doc. No. 60, official letter of March 29, 1872, says "he is credibly informed that at the time the canal was opened the bay was 8 inches higher than the lake." Prior to the opening of the canal, con |