38 Qn the Phcsnomcna of Eleclricity. 



hours each ; after which the clock was moved back again, ex- 

 actly to its former place, and another series was tried with the 

 long pendulum of three hours : after this series was completed, 

 the clock and maintaining power were both taken away, and a 

 series of vibrations were observed with the sinijilc pendulum as 

 it hung from the damp, and it was foutid that in 61 minutes of 

 sideral time, the pendulum made 2560"24 vibrations. After 

 this series of the long pendulum one of the simple vibrations of 

 the short pendulum was tried, for which purpose the point of 

 suspension was lowered 60 inches ; and in 32 sideral minutes it 

 made 2708 vibrations, also in 72 sideral minutes as tried again 

 it made 6094 vibrations, but the last mmdjcr being a little doubt- 

 ful, another trial was made, and in 62 minutes were made 5248 

 vibrations: a trial of the long pendulum was then repeated, 

 which in 65 sideral minutes made 2728 simple vilirations. 



After these trials were finislicd, a series of experiments were 

 made by changing the quantity of maintaining power, and also 

 by altering;' the height of the adjusting ball to the pendulum, as 

 will be seen by an inspection of the colunms. It is necessary 

 that before each trial the adjusting ball should be so situated 

 that the beater should vibrate in the same time as the pendu- 

 lum ; but I am not aware that this Avas strict]}' attended to in the 

 above series ; indeed, I believe the weight was not so proportioned 

 as to give an accurate result in this respect, as I remember Sir 

 George intended to repeat the series at some future period : but 

 his death put a stop to all further research. The clock is now in 

 the hands of the Hon. C. Jenkinson, in consequence of his mar- 

 riage with the daughter ot the late Sir George, and I have no 

 doubt he would be hap])y to give to any gentleman or society of 

 gentlemen, who may be desirous of prosecuting these valuable 

 experiments, by which the length of the seconds pendulum 

 might be determined to almost any degree of exactness. A series 

 of such experiments made in different latitudes would determine 

 better than any other means the figure of the earth; the clock 

 will admit of considerable* improvement, and proportional and 

 invariable impulse may be easily given to each length of pen- 

 dulum ; also various lengths might be tried, besides these se- 

 lected by Sir George, and given above. 



X. On the Phcenomena of Electricity. By J. Muicray, Esq. 

 Lecturer on Chemistry. 



To Mr. Tilloch. 



Sir, — r OoME of my experiments are recorded in the pages of 

 your Journal, which go far to establish the existence of a current 



aud 



