112 Mr. Baily's Experiments with the Torsion-rod, 



new circumstances, and with all the improvements of modern 

 artists, had consequently been frequently discussed amongst 

 scientific persons: and in the year 1835 the Council of this 

 Society appointed a Committee for the express purpose of 

 considering the subject. No effective steps, however, were 

 taken even by this body for carrying the measure into execu- 

 tion till the autumn of the year 1837, when Mr. Airy, the 

 Astronomer Royal (one of the Vice-Presidents of this Society), 

 applied for, and obtained from his late Majesty's Government, 

 a grant of 500/. to defray the expenses of this object. 



Mr. Baily having offered to undertake the laborious task of 

 making the proposed experiments, and of computing the re- 

 sults, the whole arrangement of the plan, and the entire exe- 

 cution of the work, was placed at his disposal and under his 

 control. 



It is somewhat singular, that, whilst this plan was in agita- 

 tion in this country, a similar course of experiments had been 

 actually undertaken and accomplished by M. Reich, Professor 

 of Natural Philosophy in the Academy of Mines, at Freyberg 

 in Saxony; an account of which was read before the German 

 Scientific Association, which met at Prague in September 

 1837; and an abstract of the results was printed in the 

 Monthly Notices of this Society, for December following*. 

 Though the experiments are, on the whole, in good accordance 

 with the general result obtained by Cavendish, yet they do 

 not interfere with the plan that this Society had in contem- 

 plation ; which was not merely to repeat the original experi- 

 ments of Cavendish in a somewhat similar manner, but also to 

 extend the investigation by varying the magnitude and sub- 

 stance of the attracted balls — by trying the effect of different 

 modes of suspension — by adopting considerable difference of 

 temperature — and by other variations that might be suggested 

 during the progress of the inquiry. Reich made use of one 

 mass only, and that much inferior in weight to the two adopted 

 by Cavendish. The weight of Reich's large ball was little 

 more than 99 pounds avoirdupois; whilst the two spheres, 

 used by Cavendish, weighed nearly 700 pounds. Reich's ex- 

 periments also were (like Cavendish's) too few in number; 

 57 only having been made, from which fourteen results have 

 been deduced j the mean of which makes the density of the 

 earth equal to 5'44, almost identical with that of Cavendish. 



As a great portion of the apparatus, which had been ordered, 

 was at this time actually completed, and the remainder of it 

 in considerable progress, Mr. Baily resolved to proceed in the 



[* This abstract appears in Mr. Baily's preliminary paper, already re- 

 ferred to. — Edit.] 



