July 20, 1SS3.] 



SCIENCE. 



Plotting the monthly numbers, it will be seen 

 that there are plain indications that the niaxi- 

 niiim has passed, though it is thought by some 

 that it is still to come. H. A. II. 



FIFTEENTH ANNUAL CONVENTION OF 

 THE AMERICAN SOCIETY OF CIVIL 

 ENGINEEliS.—l. 



TnK members of the society began to 

 assemble in Chicago as earl}- as Thursday, 

 June 14, to visit the exposition of railway ap- 

 pliances, and to lake part in the excursions 

 planned for their benefit by the Engineers' cluli 

 of the north-west. 



B3' Jlonday morning, June IS, the number 

 of those intending to take the special train for 

 St. Paul, generously tendered by the officers 

 of the Chicago, Milwaukee, and St. Paul rail- 

 waj', had swelled to three hundred. The train 

 of eight cars, well tilled, left Chicago at 7.30 

 A.M.. arriving at St. Paul at 10 p.m. But few 

 stops were made on the way, the princii)al one 

 being at the crossing of the Wisconsin River, 

 for the object of inspecting the railway bridge. 

 and taking a better view of the fine scenery at 

 that point. Quite an accession to the part}- 

 came on board at ^lilwaukee. 



Upon reaching .St. Paul, an engine of the 

 St. Paul, Jlinueapolis, and Manitoba railroad 

 was attaelied ; and the train was drawn over 

 that line, through Minneapolis, to Lake Miu- 

 netonka, — a beautiful sheet of water some 

 thirty miles long, where, at Hotel Lafayette, 

 thirty-three miles from St. Paul, the members 

 of the society and their invited guests were to 

 be quartered during the convention. 



The two cities of Minneapolis and St. Paul, 

 only a few miles apart, and each containing 

 over eighty thousand inhabitants, were rivals 

 for the opportunity of entertaining the society ; 

 and to prevent any ill-feeling, as well as to 

 avoid crowding any of the city hotels, already 

 taxed to accommodate their own patrons, this 

 summer hotel, just opened for the season, only 

 built one year, newly enlarged and furnished, 

 and C'lpable of providing for the comfort of 

 five hundred or six hundred guests, was chosen 

 for headquarters. With the exception that 

 some valuable time was lost in going to and 

 returning from the place of holding the daily 

 sessions, this selection is to be commended ; 

 for the location was extremely' pheasant, and 

 the air fresh and cool. Those who did not 

 desire to go to the meetings each day coukl find 

 rest and enjoyment at this agreeable summer 

 resort. A special train was at the service of 

 the convention each day throughout the entire 



week. A large accession to the number of 

 members present was made as the week pro- 

 gressed, so that the attendance was larger than 

 at any previous convention. 



On Tuesday morning tiie engineers took the 

 special train lor St. Paul, and thence went to 

 the state capitol, where the lirst meeting was 

 called to Older in Representatives' liall. After 

 formal announcements of programme and ar- 

 rangements, the usual addresses of welcome 

 were made. 



The first paper read was by the Kate Major 

 F. U. Faniuhar, U.S. eng.. on the building of 

 the dike for the preservation of the Falls of St. 

 Anthony. 



The falls, which furnish the water-power for 

 the mills of Minneapolis, were first described. 

 A stratum of upper niagnesian limestone, eleven 

 feet thick at the lower edge, is underlaid by an 

 extremely soft sandrock, which is rapidly worn 

 away ; and the limestone is thus undermined 

 and broken olf. The recession of the falls was 

 rapid ; and, as the limestone outcrops with a 

 thin edge twelve hundred feet above the pres- 

 ent brink of the falls, their final reduction to 

 rapids would occur, if not prevented. Citi- 

 zens dug a tunnel for a tail-race in the sand- 

 rock, and the rivpr broke in at the upper end. 

 The immediate destruction of the falls was 

 imminent ; and attempts to check the rush of 

 water, which rapidly enlarged the tunnel and 

 repeatedly broke througii in ditlerent places, 

 proved ineffectual. The citizens, after building 

 eotfeidams at various weak points, discouraged 

 by failures at times of high water, obtiained an 

 appropriation from the U. S. government, on 

 the ground that the wearing-away of the falls 

 would injure navigation above. A plan was 

 finally proposed by Major Farquliar, of exca- 

 vating a tunnel across the entire river, through 

 the sandrock, from the limestone overhead to 

 the sound rock below, some forty feet, and 

 filling it solidly with concrete. This work was 

 carried out under his direction, and was full}- 

 explained in the paper, and illustrated by 

 drawings. The dike is eighteen hundred and 

 seventy-five feet long, and has successfully shut 

 otf the water which worked its way through 

 the soft sandstone. The detailed statement 

 and cost can be found in the Report of chief 

 of engineeis. U.S. A , for 1.S71). The action 

 of the water has been injudiciously concen- 

 trated upon a limited S|)ace of some three 

 hundred feet by the erection of wiug-dains by 

 the mill-owners. 



In the discussion on this paper at the time 

 of its reading, and in remarks made the next 

 morning by the engineer officer now in charge 



