this time) than four or five rods, the motion of' the wheel on its axis, or shaft, ceased altogether, and it began to turn on its axis down the stream~ slowly at first~ but quickly increasing. And after the skiff had floated not more (l think) than fourteen or fifteen rods from the place where it had been an. chored, the water wheel turned downward% or with the current, as often as once round in the distance of a rod, or less. It is evident that while the wheel turned up the stream, the current of the river went faster than the skiff, or ran past it ; and when the wheel turned down the stream~ the motion of the skiff was more rapid lhan that of the current. We expected this result in a certain degree, but all of us were surprised that the floating skiffshould so soon acquire a velocity greater than that of the current of the river. It would be interesting to repeat this experiment under change of circum. stances. For instance : 1. In a slower, and in a more rapid, current. 2. In a boat heavily, and one lightly~ loaded. 3. in a flat bottomed, and in a sharp keeled, boat° 4. On rafts of different sizes. Also, to ascertain whether any difference would arise from haviog the load lie in the bottom of the boat, such as a quantity of pig metal~ or having the load consist of men standing up in the boat. Times and distances should, of course~ be accurately noted. E~
L'stimate of the ~Fater discharged by a River. If the currents of rivers diminish from the surface towards the bottom: and be very slow at the bottom~ the quantity of water discharged by rivers into the ocean is much less than has been usually imagined. Dr. Halley~ in his theory of thd origin of spring% probably estimates much too largely the quantity of water poured into tim ocean by all the rivers of the world. W h e n the dam at Fairmount~ near Philadelphia, was erected across the Schuylkill, it was slated~ in some of the newspapers, that some gentlemen wished to ascertain the quantity of water that flowed in the river in a given time. " For this purpose~ the newspapers said that the breadth and depth of the river at Fairmount were measured, and that to obtain the velocity of the motion of the water in the river~ four or five gentlemen entered a boat~ and floated a certain distance on the river~ noting the lime required to pass a given distanc% aIter the boat had acquired its natural velocity and motion~ as it was called. If the newspaper account was correct, it would seem that two great errors entered into the calculation. .First. T h e current diminished in velocity from the suriZace to the bottom~ the current in the bottom of rivers being very slight, unless in places where the descent in the bottom~ or bed, is considerable, as at rapids or ripples. Second. T h e boat loaded with tour or five men floated much faster than the fastest part of the current of the river, faster than the current at the surface. E.
J2nnual Meeting, T h e Annual Meeting of the Institute was h e l d a t their Hall~ on Thursday evening, Jan. 19th~ 1837~
JAMESRO~.~ALDSON~President, presiding; IsAAc B. GARRIGV~S,Recording Secretary, P. T. The minutes of the last Quarterly Meeting were read and approved. Donations of books were received from the Lords Commissioners of the .Admiralty, through William Vaughan, Esq., of London; A. L. Elwyn, M.D.; l~rot. A. D. Bache; Hon. James Harper; and Messrs. Mordecai D. Lgwis~ Daniel Groves, Abraham Miller~ and Edward H. Gill. Tbomas U. Waiter, Esq., presented an engraving of the Girard College. Messrs. John F. Frazier and John C. Trautwine presented specimens of minerals. Mr. Joseph Brano presented plaster casts of specimens of" the Trilobites. Mr. Henry D. Campbell presented a model of a bridge, constructed upon Town's plan. The Actuary laid on the table the periodicals received during the past quarter~ in exchange fbr the Journal of the institute. The annual report of the Board of Managers was read, and~ on motion~ was accepted, and referred~ tbr publication, to the Committee on Publications. The Treasurer presented iris report of the thnds for the last quarter~ and also a statement for the year ending December 31, 18g6~which were accepted. The Chairman of the Committee on Publications presented the report on the operations of the Journal of the Institute, for the year ending December 31, 1836, which was accepted. The Chairman of the Committee on the Explosions of Steam Boilers presented the general report of that committee, which was accepted. Mr. John Horten, from the Committee of Tellers appointed to receive the votes of the members for officers and managers of the institute for tim ensuing year, presented their report of the result of the election, when the President declared the following gentlemen duly elected: JAMaS ROrqALDSO~,Piesident. lSAIAHLUICENS~ ? THOMASI?Lv;TettEn, Vice Presidents. ISAACB. GAaamuEs, Recording Secretary. ls.~ac HAYS, M. D., Corresponding Secretary. F,~EI)ERlCI~FICALEY,Treasurer. IVlanagers. Samuel V. Merrick, Alexander M'Clurg~ Abraham Miller~ Joseph S. Walter, Jro William H. Keating~ Samuel Huffy, Rufus Tyler, John C. Cresson, John Struthers~ James M. Linnard, Matthias W. Baldwin, Andrew M. Eastwick~ Alex. Dallas Bache, Isaac P. Morris, Benjamin Reeves, Earl Shinn, J. Henry Bulkley, *Cilarles B. Trego, Alexander Ferguson, *Henry Troth, John Agnew, *John S. Warner 9 John Wiegand, ~Willliam Hart Carr. (Extract from the minutes.) JAMES tlO~ALDSOI%Pres[denL ISAACB. Ga~m~as~ .Rec. See. P. T. * New members.