380 Intelligence and Miscellaneous Articles. 



A carefully turned spherical ball of lead, 5'2 inches in diameter 

 and weighing about 17 lbs., was emjiloyed as the weight, and sus- 

 pended in the passage of the Quebec Music Hall, where a height of 

 60 feet was obtained. This weight wars suspended by a fine steel 

 wire, on one end of which a fine screw was turned, by means of 

 which the wire was fastened to the ball from which the pendulum 

 was suspended. 



The following were the arrangements adopted by your Committee 

 at the point of suspension. A small spherical ball of brass was 

 ground into a hemisphere in a plate of the same metal. A hole was 

 drilled through the centre of the hemisphere for the wire, and suffi- 

 ciently large to allow the pendulum to vibrate in the required arc 

 without coming into contact with the plate. The wire was screwed 

 into the ball of suspension. 



In order to start the pendulum for the experiments, a cotton 

 thread was passed round the ball and tied over two pins in a heavy 

 moveable block. When the weight secured in this manner had 

 been brought to a state of rest, the thread was fired with a taper, 

 and the pendulum commenced vibrating, the thread falling to the 

 ground. A circle, 10 feet in diameter, was described on the floor 

 from a centre under the point of suspension, and graduated into 

 degrees, by which the progress of the plane of vibration was mea- 

 sured. 



The first series of observations recorded in the tables were made 

 on the 14th, 15th and 16th; and the second series on the 19th and 

 20th of May. 1853. 



The first series of observations gives the angle actually moved 

 through in 47'' 18™ (after applying the correction for the progression 

 of the apse due to elliptic motion) only 1° 56' less than that calcu- 

 lated. The second series gives an error of 2° 2' in 23'* lO"". These 

 errors may be represented in time by about 10 and 12 minutes ; and 

 3'our Committee consider that these experiments agree so nearly with 

 calculation as to be strong corroborative evidence of the correctness 

 of the theory, that the time taken by the plane of vibration to per- 

 form a complete revolution varies approximately as the time of the 

 latitude. 



It may not here be out of place to give an explanation of the 

 accompanying tables. Columns (1) and (2) refer to the times of 

 observation ; (3) denotes the nature of the ellipse described by the 

 pendulum, showing, if there be no elliptic motion, or if elliptic 

 motion, whether it is progressing or retarding ; (4) shows the azi- 

 muthal angle observed ; (5) the angle moved through, and (6) the 

 time between the oljservations ; (9) is the angle calculated ; (7) is 

 the difference between (5) and (9) ; (8) is the angle corrected for 

 elliptic motion; and (10) is the difference between (8) and (9). 



Your Committee have great satisfaction in submitting the results 

 of the different experiments. In some instances they have varied 

 considerably from the calculated angles ; but in all these the fact 

 that the pendulum had acquired an elliptic motion, would seem to 

 point to that circumstance as the chief cause of disturbance, while 

 in most of the experiments in which there was no elliptic motion. 



