28 REPORT — 1S60. 



core, for the purpose, in the first instance, of determining the exact position of the mag- 

 netic equator (which passes through his territory) and the variations of intensity about 

 the line of no inclination. This part of the survey was performed with considerable 

 care, stations being chosen along the line of coast, at distances of from 10 to 15 miles, 

 generally far from the chain of the Ghats, and in a flat country, covered in many 

 places by backwaters or lagoons. The instrument employed was the excellent theo- 

 dolite magnetometer of Dr. Laraont. The results were, that the magnetic south in- 

 clination, instead of diminishing regularly from Cape Comorin northwards to the line 

 of no dip, diminished through a space of 30 miles, increased through a similar space, 

 and again diminished in the most capricious manner. The same irregularities were 

 observed north of the estimated position of the equator. Some irregularities had 

 been already observed by Mr. Caldecott, Mr. Taylor, and General Cullen; but the 

 author had confirmed his results by observations at many different stations, and had 

 come to the conclusion that a belt of disturbance for this element existed near the 

 line of no dip. This disturbance could not be attributed to the influence of hills or 

 of rocks, as no ground of greater elevation than 30 to 40 feet existed within several 

 miles of those stations showing the greatest irregularities, no rocks were reached by 

 borings of 30 to 50 feet deep, and none appeared upon the surface above the sandy 

 soil near these stations. 



The survey was extended by the author on his way to Europe by observations at 

 stations further north than those in Travancore, as Kodungalur, Kalikut, Mangalur, 

 Goa, Rutnagherri, Bombay, and Aden. From this and the first part of the survey, 

 the author found that the horizontal intensity was nearly the same from Cape 

 Comorin to Bombay, showing, as the author conceived, that the lines of equal inten- 

 sity followed (somewhat like the isothermal lines) the line of the Indian coast. This 

 result agrees with that obtained by the Messrs. von Schlagintweit, whose previous 

 observations iudicate a great bend of the isodynamic lines from the Himalayas and 

 towards Cape Comorin. The whole question, the author conceived, required careful 

 examination by means of observations at more numerous stations, as the theory of 

 the causes of the earth's magnetic intensity, and the arrangement of the magnetic 

 lines, were evidently involved in results which differed so much from what had been 

 found elsewhere, especially from the results obtained by Dr. Lamont from his admi- 

 rable magnetic survey of the greater part of the European Continent. 



On the Velocity of Earthquake Shocks in the Laterile of India. 

 By John Allan Broun, F.R.S. (See Geology.) 



On a Mode of correcting the Errors of the Compass in Iron Ships. 

 By A. Clarke, New South Wales. 



On Electrical Force. By Sir W. Snow Harris, F.R.S. 



The author adverted to the assumed existence in nature of an electric fluid or 

 fluids, an idea entertained by philosophers from the earliest periods of the history of 

 electricity. Many thought that all bodies expire or inhale this fluid. In modern 

 times less ambiguous views have been resorted to, and the doctrine of an electric 

 fluid or fluids has been employed principally as aiding to link the phenomena into 

 an intelligible and connected chain. The author thinks the time is fast approaching 

 when it may be found desirable to abandon all idea of electrical fluids as the agency 

 concerned in the development of electrical force, and treat this species of force as 

 Newton did gravity, without any care as to its occult quality. For although it may 

 be convenient and perhaps useful to employ analogical expressions in interpreting 

 the phenomena and to facilitate description, as when we speak of the quantity of 

 electric matter, of its tension, density, or thickness of stratum, &c, yet it must 

 ever be remembered that, in using this figurative language, it is force and the laws 

 of force with which we are dealing, and not with electrical fluids or other assump- 

 tions as to its occult nature or quality. 



