August 29, 1902.] 



SCIENCE. 



343 



calculations in aeronautics, particularly in 

 the theory of mechanical flight. 



Long Distance Electric Transmission Re- 

 garded as a Hydrodyimmic Phenomenon: 

 Henry T. Eddy, University of Minne- 

 sota. (A full abstract will be published 

 later.) 



The Effect of Weeds and Moss upon the 

 Coefficients of Discharge in Small Irri- 

 gating Canals: J. C. Nagle, College Sta- 

 tion, Texas. 



This paper gave the results of a half 

 dozen measurements made during the sum- 

 mer of 1901 upon small irrigation canals 

 discharging from about three and one half 

 to twelve cubic feet of water per second, 

 and will show the retarding effect of moss 

 and weeds in some of the canals. 



The Compound Pendulum : Albert Kings- 

 bury, W. P. I., Worcester, Mass. 

 The paper referred especially to a dia- 

 gram by means of which the relations be- 

 tween the centers of suspension, of gyration 

 and of oscillation are graphically deter- 

 mined ; the identity of centers of percussion 

 and of oscillation ; the interchangeability of 

 centers of oscillation and of suspension; 

 the position of the axis of siispension for 

 minimum time of small oscillations; and 

 the two cylinders of positions of the axis of 

 suspension for any given time of oscillation. 



Crushed Steel and Steel Emery; an Arti- 

 ficial Abrasive produced from Steel: M. 

 M. Kann. 



The Mechanics of Reinforced Concrete 

 Beams: AV. Kendrick Hatt. 



A Test of a Ball Thrust Bearing: Thomas 

 Gray. 



Determination of the Exponent in the 

 Eq^iation pv" of Heat Engine Indica- 

 tor Diagrams: "W. T. Magruder, Ohio 

 State University. 



Some Experiences with a Simple Babbett 

 Testing Machine: B. S. Farwell, New 

 York. 



In order to select the most suitable 

 babbett metal for use in paper mills a series 

 of tests were undertaken with a machine 

 consisting of a three and one fourth-inch 

 mandril rotated at about 775 revolutions. 

 The test block was held against the bottom 

 of this mandril by a long bent lever to 

 which weights were applied. The block and 

 mandril were immersed in oil. After a 

 number of failures which are described, and 

 the discovery that the readings of the ther- 

 mometer were vitiated by the heat from the 

 main bearing the macliine was remodeled. 

 As remodeled it consisted of the same 

 mandril and two test blocks held against 

 opposite sides by a pair of levers acting like 

 nut crackers. The weights were added to 

 the outer end of the upper lever, while the 

 outer end of the lower lever rested on a 

 platform scales. The other end of the levers 

 was counterbalanced so as always to pro- 

 duce an equal pressure on both blocks. As 

 thus reconstructed the coefficient of fric- 

 tion may be determined as well as the 

 breaking load. Observations on several 

 methods of lubrication are given as well as 

 other experiences with this simple but 

 accurate testing machine. 



Notes on the Electrical and Mechanical 



Equipment at the Charleston Exposition: 



J. H. Granbey, Elizabeth, N. J. 



A short paper giving a resume of the 



data regarding operation and equipment of 



the exposition at Charleston, S. C. Some 



details of interest in the installation of 



temporary underground lines are given, 



and attention is called to some departures 



from the accepted practice in engineering 



work, used for special features. 



The following papers were presented by 

 title : 



