1857.] Report on the Progress of the Magnetic Survey. 99 



1855 ; and these comparisons will facilitate in a great measure the 

 determination of the absolute values of the magnetic force for the 

 different stations of observations. 



All the magnetic instruments have remained in perfectly good 

 order throughout the season. 



My brother and myself had wished to subjoin to this Eeport 

 a more elaborate resume of the results of the magnetic observations 

 now extending over a pretty considerable part of India, together 

 with a map showing the magnetic curves ; but we found such a 

 work, with any attempt at the necessary accuracy, would have 

 taken at least one or two months ; so great an interruption of our 

 movements would have necessitated a complete alteration of the 

 plan of our operations during the ensuing season, and it would have 

 been probably quite impossible to extend our researches for the 

 present year into the most distant parts of the "Western Himalayas. 



Every one acquainted with the details connected with the final 

 reduction and calculation of scientific data, like magnetic and other 

 physical observations, will agree that it is quite useless to publish, 

 in a hurry, provisional figures and results, which would all have 

 to be cancelled and re-calculated for the final computation of the 

 work. 



We expect, if no unforeseen accident interrupts our progress, 

 to be able to return to Europe in one year and a half, and we shall 

 then endeavour to reduce and publish the results of our magnetic 

 and other researches with the greatest regard to the accuracy 

 necessary for final results, which may perhaps not prove quite 

 unworthy of the patronage bestowed upon our scientific researches 

 by the Court of Directors. 



As a general result of our magnetic observations, I mention the 

 fact, that the magnetic intensity increases in India from the South 

 towards the North much more rapidly than might be expected 

 from a consideration of the geographical latitude only. If the 

 curves of the dip of the needle are laid down on a map, it is plainly 

 seen that the spaces between them are very narrow when compared 

 with other parts of the world. 



Thus, in North West India, in a latitude of 30 and 31 £ degrees, 

 the dip of the needle is already as much as from 11 to 43 degrees. 



o 2 



