5<g EXPERIMENTS ON CURRENTS. 



Experiment I supposed, that the best form to be given the wood for 



(Th 1 n" making the experiment would be globular, as being less lia- 



ble than any other to be affected by irregularities in the 

 surface of the water. I caused two wooden balls to be made, 

 one of oak G inches in diameter, the other of fir, and not 

 so large. I chose a time when the quietness of the air was 

 next to calm, and the surface of the water very smooth. 

 The balls were put into the stream ; the oak swam deep, 

 leaving a very small portion uncovered ; but the fir ball was 

 found so very susceptible of motion from the lightest air of 

 wind, that no conclusion could be obtained from this expe- 

 riment, 

 with a staff It was suggested by Mr. Rickman, my associate in these 



loaded at one experiments, and whose observations jointly with my own 

 have furnished this paper, that for showing the direction of 

 the current, a long staff of light wood, loaded at one end, 

 might better answer the purpose than two unconnected 

 floating bodies, because whenever it got out of the right di- 

 rection it would have a tendency to correct itself. 



On Wednesday, July 27th, we made some experiments 

 on the river; but the weather was not favourable. Two 

 sticks, one of them a common walking stick with a piece of 

 lead fastened to one end, the other a hollow tube (a joint 

 of a fishing rod) loaded internally at one end, were put into 

 the stream (but not in any preconcerted or remarked direc- 

 tion) and they both took the direction of the stream, the 

 heaviest end becoming the most advanced. They were taken 

 up, and being again put into the water in a direction oppo- 

 site to the stream, they gradually regained their former di- 

 rection : in what time was not observed. In endeavouring 

 again to repeat the experiment, two barges passing caused 

 us to lose sight of our sticks, and we did not find them af- 

 terwards. 

 Fassage of boats About an hour after the flood had made through London 

 through the | 3r i < jgr e) I noticed from the top of the bridge the passage of 

 some of the craft. When any one drew near the arch, she 

 did not keep pace with the water before her, so that on 

 looking only at her head, she seemed to have stern way ; 

 but at her stern she left the marks of her track behind her,. 

 Two barges and a small boat, the small boat being in the 



middle 



