Nauvoo is on east side of the west, north, and south street that runsnearly across the bottom land in front of the town of Nauvoo, Ills. A large farm of small fruit lies west of street to river. A fruit barn stands on west line of street opposite station. A two-story brick house stands east of station 200 feet. South end of street at river is just above slaughterhouse. Geodetic point marked by copper bolt in tile, surmounted by iron pipe.

O Sand Ridge is on Iowa side and about 14 miles above Montrose, on a sand ridge on west side of wagon road, 10 feet inside of fence. Railroad adjoining wagon road on east side. Station is 300 meters below Milepost 30, and about 300 meters above a small shanty near corner of hedge fence. Geodetic point marked by usual copper bolt in tile and iron pipe.

Macuta is on Iowa side of river, 5 miles below Fort Madison, 4 feet north of fence on north side of right of way of Chicago, Santa Fe and California Railway, 200 feet northeast of southwest switch stand of siding, about 450 meters above (northeast) Howe truss bridge over Devils Creek, 70 meters (distance paced) northeast along railway fence from a north and south fence. Geodetic point marked by a copper bolt in usual tile, surmounted by iron pipe projecting 4 inches above ground.

Fort Madison is on Iowa side, on top of bluff, just above north and south fence about 1 miles back of river. Fence runs across bottom, just below foundry shops of Chicago, Santa Fe and California railway. A two-story brick schoolhouse stands directly south of station on street on which street cars run to Fort Madison. Station is about 2 miles below the town. Geodetic point marked by copper bolt in flat tile and surmounted by iron pipe.

Sherman is on Illinois side of river, 24 miles above Nauvoo, on bluffs in timber, about 200 meters below where steep rocky bank of river ends and flat bar, partly covered with large willows, begins, back of and a little below the remains of an old foundation wall standing on river bank. Station stands on a projecting point in ridge 75 meters in front of fence at edge of clearing. Geodetic point marked by usual copper bolt in tile, surmounted by iron pipe. Several trees 10 to 12 inches diameter were cut around station. It is about 100 meters below B. M. 6 which stands on side of road at foot of hill. A house stands on crest of bluff about 400 meters above.

A Penitentiaryis on Iowa side on crest of steep bluff above ravine just above new reservoir of Fort Madison city waterworks. Station is on narrow ridge parallel with river and 75 meters above end of ridge. A two-story brick house stands 300 meters back of and a little below station, which is 10 feet from crest of bluff on river side. Geodetic point marked by copper bolt in tile, surmounted by iron pipe projecting 14 inches out of ground. About 1 mile above Fort Madison railroad bridge.

Niota is on Illinois side of river, on top of bluff, about 1 mile below Chicago, Santa Fé and California Railway bridge at Fort Madison. It is 6 meters back of crest of bluff on a small mound, about 100 meters below where bluffs turn back from river. It is almost directly opposite railroad depots in Fort Madison. Bluffs timbered. It is in front of and a little above a fence corner at northwest corner of clearing. Geodetic point marked by usual copper bolt in tile, surmounted by iron pipe projecting 8 inches out of ground. Line cut through timber to Appanooce.

Appanooce is on Illinois side of river, in cultivated field, 20 meters above telegraph pole on which is fastened two hundred and thirty-fourth mile board Chicago, Santa Fe and California Railway, and 30 meters west of west right-of-way fence. Road crosses railroad about 300 meters above station. It is about 2 miles above Niota, Ill. Geodetic point marked by usual copper bolt in tile, surmounted by iron pipe projecting above ground 1 foot. It is about three-fourths mile back from river bank.

Lomax is on Illinois side, on top bluffs about 800 meters above Milepost 13, Carthage branch of Chicago, Burlington and Quincy Railroad, 23 miles above Dallas City. Station is on crest of bluff back of small field used for pasture, 250 meters above house. It is on the upper one of three small ridges which form the point on the bluff line. Geodetic point marked by usual copper bolt in square tile, surmounted by iron pipe projecting 4 inches above ground.

Dallas is on Illinois side, on bluff about three-fourths mile below Dallas City. Station is 6 meters south of picket fence running down the bluff. A dry creek running out of small ravine just above station runs through Bridge 320 on Chicago, Santa Fé and California Railway. Geodetic point marked by small copper bolt in tile, surmounted by iron pipe projecting 10 inches above ground.

Westcott is on Iowa side, on top of bluff, about one-fourth mile below (toward Fort Madison) Milepost 15, St. Louis, Keokuk and Northwestern Railroad. In corner of fence at jog in road. A two-story brick house stands on crest of bluff where road goes down bluff about 300 meters above station. Geodetic point marked by usual copper bolt in tile, surmounted by iron pipe projecting 10 inches above ground. Line cut to penitentiary.

Carman is on Illinois side, on bare bluff, on land owned by James Perry, 3 miles

east of Carman. An east and west road crossing the railroad ends at fence at foot of hill, 150 meters north of station. A hedge fence runs north and south 40 meters west of station. An east and west board fence is 60 meters south of station. A twostory white frame house stands 200 meters above station on hill. Station is on small knoll above gully, and is not on highest part of bluff. Geodetic point is marked by usual copper bolt in tile, surmounted by iron pipe projecting 2 inches above ground. Wever is on Iowa side in bottom, about 2 miles southeast of town of Wever, on land owned by George Tucker. It is 200 meters east of road, in pasture 1 meters east of fence. A small one-story frame house stands on west side of road nearly west of station. Schoolhouse stands on road 200 meters south of house. Geodetic point marked by usual copper bolt in tile, surmounted by iron pipe.

Patterson is on Iowa side, on crest of bluffs, 75 meters above Milepost 5, St. Louis, Keokuk and Northwestern Railroad. At wire fence running along bluff. A house stands opposite the milepost at foot of hill. Geodetic point marked by usual copper bolt in tile, surmounted by iron pipe projecting 8 inches above ground.

Burlington is on crest of bluff in South Burlington, on line of fence on north line of alley south of Polk street, and 2 meters from end of fence, about 200 meters below bridge. Geodetic point marked by usual copper bolt in tile.

Sater is on Iowa side on crest of bluff about 6 miles above Burlington. A oneand-a-half story frame house stands on east side of road about 100 meters south of station. Bluff is partly wooded. Road runs up bluff 800 meters south of station. House at foot of bluff is painted dark red with white trimmings and is not occupied. Geodetic point marked by usual copper bolt in tile, surmounted by iron pipe projecting 14 inches above ground.

Gladstone is on bluff south of town of Gladstone, Ill. Old distillery stands 200 meters southwest of station at foot of bluff. Station is in pasture 300 meters east of main street of town running south from depot, and 100 meters south of south street of town, 10 meters north of fence. Geodetic point marked by copper bolt in tile, surmounted by iron pipe projecting 2 inches out of ground.

Ellison is on Illinois side, in bottom opposite lower part of Burlington, about 3 miles back from river and one-half mile below Ellison Creek. It is on sand ridge 75 meters south of east and west road and 400 meters east of where Carman and Burlington road turns south. A house and large red barn stand 150 meters north of station. Geodetic point marked as usual.

Henderson is on Illinois side on bluff 3 miles above Oquawka station. Is on projecting point of bluff near where Henderson river comes to bluff. A house stands at foot of bluff 1,200 meters south and one on bluff 300 meters directly back of station. Geodetic point marked by copper bolt in tile, surmounted by pipe projecting 8 inches out of ground. Station on land owned by Mr. H. P. Burghet.

East base is on south side of track of Chicago, Burlington and Quincy Railroad at foot of low embankment and three telegraph poles west of crossing just west of milepost No. 47. Geodetic point marked by usual copper bolt in tile, surmounted by iron pipe.

Elevation of east base, 598.28.

West base is on north side of right of way of Chicago, Burlington and Quincy Railroad, 3 meters south of right-of-way fence, 300 meters east of east road crossing in town of New Boston. On highest part of ground through which railroad has been cut. Geodetic point is usual copper bolt in tile with pipe projecting 8 inches. Elevation of west base, 583.96.

New Boston base line was measured along south side of track of Chicago, Burlington and Quincy Railroad running east from New Boston.

Sturgeon is on Illinois side on top of bluff 5 miles north of New Boston. It is nearly on line with the north and south main road from New Boston to Muscatine. A small white house stands on bluff side of road, 100 meters south of station. It is 12 meters south of fence running up bluffs at south end of orchard.

Bald Bluff is on highest point of "Bold Bluff" on Illinois side, 63 miles southeast of Keithsburg. Bluff is very prominent from all directions. Geodetic point is usual copper bolt in tile, surmounted by iron pipe projecting 8 inches. Station is on land owned by H. P. Burghet (?).

Kingston is on Iowa side about 7 miles south of Oakville. Station is on very prominent bluff. Road from Toolsboro to Burlington runs along foot of bluff. Small white frame house stands on bluff side of road a little north of station. A road runs up gully and onto bluffs about 400 meters north of station. Schoolhouse stands short distance north of fork in road. Station is on cultivated ground, 75 meters south of wire fence running down bluff to near house. Bluffs timbered 300 meters below station. Line cut to station Gladstone. Geodetic point marked by usual copper bolt in tile, surmounted by iron pipe projecting 14 inches above ground.

Toolsboro is on crest of bluffs, about three-fourths mile below Toolsboro, Iowa, on land owned by Mrs. Parsons. It is about 100 meters in front of road, in timber. Mrs. Parson's house, a two-story white frame, stands on west side of road, about 300 ENG 92- -185

meters above (north) station. Station stands on extreme edge of hill and on a little projecting point. Geodetic point is marked by usual copper bolt in tile, surmounted by iron pipe projecting 8 inches above ground.

Louisa is on crest of bluffs on Iowa side, nearly due west of Port Louisa. Station is 2 meters north of fence on north side of small cemetery known as "Cameron Cemetery," and two meters east of north and south fence running along crest of bluffs on land of Mr. Cameron. Road comes up bluff just south of cemetery. Geopetic point marked by usual copper bolt in tile, surmounted by iron pipe projecting 15 inches above ground.

▲ B. M. Pat. is at point of preliminary location of A Patterson. As it could not be used as a secondary station, the tile was left in position and a B. M. cap was placed on top of pipe. It is in field 2 meters north of hedge fence, on hill near top, abreast the 4-mile post Chicago, Burlington and Quincy Railroad. A two-story stone house, with no roof, is on slope of hill about 100 meters from stone.

The name is chosen to prevent confusion, as a secondary station, "Patterson," was chosen 1424.4 meters below on the bluffs.

APPENDIX 4 B.

REPORT OF ASSISTANT ENGINEER O. W. FERGUSON, ON FIELD WORK AND REDUCTION OF PRECISE LEVELS FROM ST. PAUL, MINNESOTA, TO SAVANNA, ILLINOIS, WITH TABULATED RESULTS AND DESCRIPTIONS OF BENCH MARKS.

OFFICE OF THE SECRETARY,

St. Louis, Mo., March 12, 1892.

SIR: I have the honor to present the following report on precise-level work from St. Paul, Minn., to Savanna, Ill.:

The double precise-level party for this work was organized at this office on April 25, 1891, and consisted of O. W. Ferguson, assistant in charge; L. M. Mann, assistant engineer; F. B. Williams, recorder; Irving W. Durfee, recorder; John P. Baker, rodman; L. B. McKeen, rodman; J. A. Warrick, rodman; R. J. Dickinson, rodman; Frank VanNess, foreman; E. J. Burgess, axman; H. M. Conradt, axman; H. M. Willson, axman; J. H. Tyner, cook; T. M. Brennan, steward.

The United States survey boat Kentucky had been assigned to this work and was lying at the foot of Barton street. Pursuant to orders from Chief Assistant Ockerson, all hands were on board ready to start up the river under tow by the United States steamer Patrol at 11 o'clock on April 25, 1891. Owing to the large number of tile and iron pipe and stores that had to be stowed away on the United States boats Illinois and Kentucky, the Patrol did not get under way until 4:45 p. m.

The secretary of the Commission, Capt. Carl F. Palfrey, accompanied the fleet as far as the head of the Des Moines Rapids Canal, where we left the United States survey boat Illinois. Chief Assistant Ockerson accompanied the Patrol all the way to St. Paul, which point we reached without damage or loss at 10 a. m. on May 2, having passed the 729 miles in one hundred and sixty-one and one-half hours, or at an average speed of 4.52 miles per hour, including stops that were made for coal, to distribute the tile bench marks (at Genoa, Wabasha, Red Wing, and Hastings), to detach and tie up the Illinois, four hours at Fountain City on account of rafts, one hour at Lake Side on account of wind, and seven and one-half hours at Hastings on account of the danger in passing rafts, logs, and numerous dikes in the night. About twenty-four hours in all was consumed in these stops, making the running speed 5.31 miles per hour.

The party was subsisted on the quarter boat Kentucky, well equipped for work, being furnished with tackle, tools, furniture, cooking outfit, table and kitchen utensils, bedding, towels, napkins, etc., no per diem being allowed, but all supplies and labor paid for by the Commission on properly signed vouchers.

The Kern precise levels Nos. 1, 3, and 5, with Kern precise-leveling rods Nos. 11, 13, 18, and 19, with the accompanying articles, were assigned to the party. They are the same kind of instruments and rods as are described in the report of the Commission for 1883, page 55.

On landing at Pig Eye, 24 miles below St. Paul, we immediately set to work to determine the necessary instrumental functions, in order for the field reduction of the work.

(1) These are the value of one division of the level tube and the distance at which it subtends 1 millimeter on the rod.

(2) The total and the relative value of the wire intervals in each instrument, thus finding the space intercepted at all distances by the wires on the rod, and their dif

ference, in order to be able to use their values subsequently to check the readings made and to find from the wire intervals obtained in all readings the length of the observation, tables being constructed at once.

(3) The amount of inequality of telescope rings to enable one to apply the proper correction to the excessive sights, it not being possible to eliminate this error by adjustment, and it not being a quantity that can be readily determined like that of inclination and collimation.

(4) The value of what has been called the "A" of rods, which is the distance from the first graduation of the rod to the bottom of the spur. Though in fact it is 100 millimeters less this quantity that is applied, all readings on the rods being 100 millimeters more than the distance above the first graduation. It is always necessary to apply this quantity when one observation (as backsight) is taken on a rod, and the other (as foresight) directly on the bench or on a rod graduated from the bottom, as when reading directly on a copper bolt leaded horizontally; also when reading the three wires directly against a gauge.

The first operation necessary is to make this distance the same for two rods that are to be used together. I devised a method for this that is extremely accurate. Owing to the two points to be measured between being in different planes, it is very difficult to measure this quantity directly. After they were made approximately equal the instrument was mounted on a stump and the rods alternately on another stump about of the same height and about 8 meters distant; the center wire was then set by elevating screw on to, say, the zero of graduation and the bubble read, and then the rod slightly filed off, which proved to be the longer, as determined by the readings of the bubble. When the bubble read the same, whichever rod was held on the spike the "A's" were of the same length. The absolute length of "A" can then be determined very closely by reading on the rod and on a stick set on the same point by measuring the difference between the length of the graduated portion intercepted and the length of stick intercepted.

The magnifying power of these Kern telescopes, determined by comparing the visual angle between the extreme wires as viewed through the telescope with the natural angle that the space intercepted between these wires subtend on a rod at the same distance, is 52.

The

Each instrument was provided with a large, square umbrella standing 5 feet high to protect it from the wind, also a smaller umbrella to protect it from the sun. rod supports for turning points were footplates or pins. Stakes with nails in their top were used whenever the ground was too soft for other supports. The footplates give excellent results on ground in which there is sand or gravel if not very loose. The pins are better for ground loose on the surface or for woodland where there is a good deal of vegetable substance in the soil.

The general health of the party seemed to be affected during the first four weeks of the work. Diarrhea was the form of attack; this was probably caused by change of water. After this the health of the party throughout was good. Assistant Mann's ill health and inexperience with this particular kind of work made it necessary to make a change in assistants. He was therefore ordered back to office on May 27. A. L. Johnson, appointed by the office as assistant, reached the field and began work on May 30. All of the party excepting the chief were inexperienced in precise level work.

On the morning of the 6th of May actual field work was begun by one party; O. W. Ferguson, observer. Afternoon of the same day Assistant Mann took same party and began work, Assistant Ferguson working with the other party.

Line of work.-It being conducive to good work to operate on hard and wellsettled ground, and it also being conducive to small probable error to shorten the line, the line of work followed the line of the railroads whenever they were accessible to the river, care always being taken to set the foot plate or pin so that they would not be disturbed should a train pass by. The rear support was never disturbed until the forward one had been fixed, thus we were always prepared to be surprised by an express or freight train; the greatest damage they could do, which was often done, was to drive the instrument from the track just before being able to complete the forward observation. Work, however, can be carried along more rapidly on railroad line than in most any other place, there being no brush to cut, no soft ground to contend with, and the grades are not sufficiently abrupt to interfere with the length of observation. This line of work continues from St. Paul along the line of the Chicago, Burlington and Northern Railroad to a point 34 miles below Diamond Bluff, where it leaves this road and follows through the country, through Trenton, Wis., crosses the slough of Island 24, down Island 24 to opposite Red Wing, where we made a river crossing by reciprocal leveling, then down along the right bank to Wacouta, where we reach Lake Pepin; continues along down the right bank of Lake Pepin to 2 miles below Lake City, a distance of 29 miles without any railroad; then, via Chicago, Milwaukee and Saint Paul Railroad, along the right bank to Wabasha, Minn.; then along the right bank without railroad or other road 8 miles, to Alma, just above

which town we made another river crossing over into Wisconsin; then the line followed the Chicago, Burlington and Northern Railroad to Winona, where we made another crossing on the Chicago and Northwestern Railroad Bridge; then we follow the Chicago, Wilwaukee and Saint Paul Railroad and cross on their bridge above La Crosse to Wisconsin, following the Chicago, Burlington and Northern Railroad to Prairie du Chien, where we cross back to the Iowa side via the trestle bridge of the Chicago, Milwaukee and Saint Paul Railroad, following this road to 4 miles below Bellevue; thence along the right bank of river to opposite Island 253, crossing over by reciprocal leveling and following the left bank a distance of 10 miles without railroad to Arnold Landing, where we reached the line of the Chicago, Burlington and Northern Railroad again and follow it to Savanna, where our work connected with the precise-level bench marks established by the Commission in 1883. Thus it will be seen that 84.4 per cent of the main line followed the railroads and 15.6 per cent followed along the river shore. It is to be noticed that this line of precise bench marks is very accessible to the river, yet they are all where they should remain for many years. Proper sacrifice was always made to keep in reach of the river.

Moving quarter boat. -The Kentucky was not supplied with steam power. Her timbering was very weak, though the planking was quite good. The boat was dropped by hand from point to point as the work progressed. This was done as far as possible when it was calm. At such times the work of moving the boat was easy, but it was not possible always to wait for calm weather. Also when it appeared to be calm in one place it would be quite the contrary a mile or two distant. No little anxiety was felt in passing the many dikes and along the riprapped shores toward which the boat would often manifest a strong attraction, what with the wind and current trending to the bank, sometimes it scraped the rocks. At the head of Island 46, coming suddenly under the protection of the timber, the wind having before kept the Kentucky off the shore, she all at once started for land, and crushed a skiff before she stopped against the bank, which was of earth. From the start throughout the season improvement was made in handling the boat. The best results could be obtained by the crews of six oars each in the front, a sweep on each side in front, and a steering sweep behind. In this manner we moved the boat when the wind was quite adverse; often all this power would be required to keep the boat off the shore while she drifted with the current. The most dangerous navigation was through Lake Pepin. The bluffs are very high, and the wind uncertain, blowing only in spots and in different directions. Out in the lake it may blow offshore, while under the bluffs there will be an underwhirl that blows toward shore. This last drove us to the rocks a couple of times in spite of all we could do, but with the aid of pike poles she touched quite gently; then by hitching a line pretty well back she was towed to harbor. At Kings Coulee such a violent storm came up that the spars gave way and the Kentucky was blown hard against the gravel, but one party reached the boat at this time, and she was kept from pounding on the bottom by props and pikes until the storm abated and the spars were reset.

Connections with old work.-The set of charts furnished me were plentifully marked with locations and short descriptions and elevations of old bench marks. These were all searched for whenever our line passed in the same vicinity, and if found, according to instructions, side lines were run to them if they could not be taken in the main line. Comparatively but few of them could be found and a large proportion of those found were in bad condition, the nails and tacks of which they were composed in several instances being rotted loose. Some quite permanent old bench marks were found in the towns along the route. The elevations of these old bench marks as given on the maps were a source of some annoyance. We never could check with them nor come within from a foot to 40 feet of any constant difference from these elevations. Through the courtesy of the Rock Island office more recent descriptions and continuous elevations and of some more recent bench marks were furnished me from time to time. In some cases this information was a little behind the progress of the work, but otherwise all of these (of which I submit the list) that were near the line of work and could be found were connected with.

All of these gauges found were also tied onto and the datum of cities passed through were connected with when there had been any datum established. In these connections with the old benches there was a general tendency to quite good agreement for ordinary levels, with some exceptions.

The elevations furnished in "gauges and bench marks" were found to vary 1.2 feet in the widest places when the elevations were subsequently determined in reference to Cairo datum. Elevations were also quite generally taken of the "base of rail" in front of depots passed on the line of work.

No old bench mark connected with was given a new number; it was designated by its old number, as B. M. " a," or, if it had no number, as old B. M. so and so.

New bench marks.-These were of two denominations, permanent and temporary. The permanent ones were located with great care, with a view to remaining an indefinite period. They were most all set where they could be easily and accurately