284? Geological Society, 



the distance of the centres of the large and small spheres, the time 

 of the oscillations, and the deviation of the arm of the balance. The 

 distance varied from 6*62 to 7 49 inches ; the duration of the oscil- 

 lations, from 6"™ 4P, to 6"^ 50«; and the deviation from '236 to 

 •315 of an inch. The greatest source of error is in the determina- 

 tion of the deviation ; the position of the arm being subject to some 

 anomalous variations caused, probably, by slight currents of air in 

 the interior of the wooden case. This source of error could only be 

 eliminated by increasing the number of observations ; but the dif- 

 ferences of the partial results actually obtained were so small that 

 the mean result may be regarded as sufficiently approximate. 



The number of observations was 57. The mean of the whole 

 gives the density equal to 5*44, a result which is almost identical 

 with that of Cavendish. M. Reich also used for the attracting 

 mass a sphere of cast-iron, of the same diameter as the leaden one, 

 and weighing 30 kilogrammes, or 463,373 grains. Five observa- 

 tions with this sphere gave the density = 5 '43. 



The public will look with much interest for further particularsi 

 respecting these experiments, in order that they may be examined 

 more in detail. The only innovations on the method of Cavendish 

 appear to have consisted in using only one of the great spheres in 

 the same experiment, and in the mode of observing the deviation of 

 the arm of the balance. The arm itself appears to have been nearly 

 of the same length as that used by Cavendish, but we are not in- 

 formed of its weight, nor of the weight of the small balls. The large 

 spheres, however, were much inferior to those of Cavendish, their 

 diameters being only 7|- inches, and weight less than 2-7ths of those 

 used by Cavendish. The employment of the cast-iron sphere is a 

 new feature in the experiment, but it does not appear that the small 

 balls were changed. 



Mr. Baily concludes with remarking that, though these experi- 

 ments are, on the whole, confirmatory of the general result obtained 

 by Mr. Cavendish, they do not interfere with the plan the council 

 of the Society had in contemplation, which was not merely to repeat 

 the original experiment in a precisely similar manner, but also to 

 extend the investigation by varying the magnitude and substance of 

 the attracting masses, by trying their eff'ect under considerable dif- 

 ferences of temperature, and by other variations that may be sug- 

 gested during the progress of the inquiry. 



A Catalogue of Moon- culminating Stars observed at Greenwich, 

 Cambridge, and Edinburgh, in the months of July, August, and 

 September, 1837. This catalogue appears in the Monthly Notice of 

 the Society, No. 10. of vol. iv. 



GEOLOGICAL SOCIETY. 

 Nov. 15, 1837. — A Letter from Walter Calverly Trevelyan, Esq., 

 F.G.S., to Dr. Buckland, V.P.G.S., on " Indications of Recent 

 Elevations in the Islands of Guernsey and Jersey and on the coast 

 of Jutland, and on some Tertiary Beds near Porto d'Anzio" was 

 first read. 



