150 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



needles of the standard compass are reduced to something like 

 half an inch in length, and not till then, will the theoretical per- 

 fection and beauty, and great practical merit of Airy's method 

 of correcting the compass be universally recognized, and have 

 full justice done to it in practice. The studies of Archibald 

 Smith in relation to compass deviations were carried on by 

 him as a labor of love, entirely distinct from his practice of 

 law. He gradually attained to an important and extensive 

 practice, and to a high reputation as a chancery barrister, 

 but never lost his interest in science, nor ceased to be engaged 

 in scientific pursuits. In addition to the love of science for 

 its own sake, he was penetrated by the conviction of the use- 

 fulness of his work ; his splendid abilities, supported by a 

 constitution of unusual vigor, were freely and heartily de- 

 voted to the service of his country and the good of his fel- 

 low-creatures. "Think how many lives it will save," was 

 his answer to an anxious friend who begged him to relinquish 

 labors so exhausting, and to give himself ordinary rest. His 

 mathematical and other scientific works appear to have been 

 entirely carried on during his vacations, his journeys, and the 

 midnight hours stolen from sleep. During the last three 

 years of his life he was compelled by illness to give up most 

 of his work, but a few months before his death, having: won- 



* j cj 



derfully rallied, he was engaged to revise the instructions 

 for compass observations to be made on board the Chal- 

 lenger, then about to sail on the great voyage of scientific 

 investigation which is still in progress. Proc. Royal Society, 

 22. 



OBSERVATIONS OX EARTH CURRENTS. 



The subject of earth currents has received considerable 

 elucidation in a discussion that is recorded in the journal 

 of the Society of Telegraph Engineers. Mr. Winter, tele- 

 graph engineer at Madras, has established two telegraph 

 lines, each two miles long, running respectively in the me- 

 ridian and at right angles thereto, both starting from his 

 office at Arconum, near Madras. The current from each wire 

 was observed on the same tangent cralvanometer, and observa- 



CD CD 7 



tions were taken hourly during December, 1871, when bad 

 health and press of work compelled their abandonment for a 

 time. Apparatus for the measurement of the two elements 



