154 Scientific Intelligence. [Fifcl 



Colonel Mudge was obliged, by ill health, to relinquish the fur- 

 ther prosecution of the summer's operations, and return to 

 England. But Dr. Gregory, Capt. Colby, and Capt. Mudge, 

 accompanied M. Biot to the Zetland Isles, for the purpose of 

 distributing among them, and carrying through, the proposed 

 experiments. The station chosen by these gentlemen in con- 

 cert, for their common operations, was Balta, a small island, in 

 north latitute 60° 45'. But as this island had no permanent 

 residences upon it, M. Biot removed to the neighbouring island 

 of Unst, where he obtained comfortable accommodations for 

 himself, and a convenient building in which to fix and arrange 

 his pendulum apparatus. Here, therefore, this gentleman, again 

 assisted by Captain Mudge, made experiments and observations 

 analogous to those which had been made at Leith ; while Cap- 

 tain Colby and Dr. Gregory employed themselves at Balta ; the 

 former, principally, in carrying through a numerous series of 

 observations with the zenith sector, for the determination of 

 the latitude ; the latter, principally, in observations with a 

 transit instrument, to determine " the rate " of Pennington's 

 astronomical clock. Other operations, of a subordinate kind, 

 need not be alluded to in this account. 



Dr. Gregoiy afterwards made observations at Marischal Col- 

 lege, Aberdeen, to determine the rate of Pennington's clock 

 there ; and on trying the clock at Woolwich Common, after its 

 return from the north, he found that its rate was precisely the 

 same as it was last April, before it was taken out on the expe- 

 dition. 



M. Biot and M. Arago have also, it is understood, made, 

 jointlv, some pendulum experiments at the Royal Observatory, 

 Greenwich ; and it is expected that the several individuals will 

 repeat the experiments and observations, in more southerly sta-. 

 tions, during the summer of 1818. 



None of the results are yet published ; nor does it seem alto- 

 gether proper that they should be, till the proposed series of 

 operations is terminated. But it. is hoped that the deductions 

 which the whole will furnish will be highly useful, in reference 

 to the real length of the seconds' pendulum, the variations of 

 gravity in different latitudes, and the approximate figure of the. 

 earth. 



VI. Explosion in a Coal-3Iine in the County of Durliam. 



The following account of another of these fatal accidents, is 

 taken from the Tyne Mercury, Dec. 23 : 



" On Thursday, Dec. 18, an explosion of fire-damp occurred 

 in the Plain pit at Rainton colliery, near to Houghton-le- 

 Spring. The total number of lives lost amounts to 26 ; 10 men, 

 and lb boys. The explosion took place at three o'clock in the 

 morning, before the hewers had descended the pit ; and from 

 this circumstance about 160 lives have been preserved. Every 



