Intelligence atid Miscellaneous Articles. 



15i 



ON THE VARIATION OF THE NEEDLE, AS OBSERVED DURING 

 A VOYAGE TO AND FROM INDIA. BY W. H. WHITE, H.M.C.S. 



To the Editors of the Philosophical Magazine and Annals. 

 Gentlemen, 



Not having seen any thing lately on the variation of the mariner's 

 compass, and having just perused the private log of a gentleman 

 recently returned from India, I have extracted a few observations, 

 showing the variation at four nearly corresponding latitudes, out- 

 ward and inward. 



Outward bound. 



Longitude. 



5'^ 30' W. 



23 30 W. 



37 00 W. 



31 00 E. 



Homeivard bound. 

 Longitude. 

 23° 00' E, 

 2 51 E. 

 18 2,5 W. 

 5 40 W. 

 In the outward passage, it appears that the variation diminished 

 as the latitude diminished and the longitude increased westward, 

 till the ship reached latitude 21° S., longitude 37° W., when it en- 

 tirely ceased. A progressive increase again took place as the ship 

 continued to sail southward, making E. longitude. 



In the homeward passage there is a regular diminution of varia- 

 tion as the ship sails westward ; and as a proof that the compass is 

 not influenced by latitude, at least in the torrid zone, we find in la- 

 titude 21° 30' S. the variation was 20° W., whereas in 21° S. in the 

 outward passage, having a difference of 39° 51' W. longitude, there 

 was no variation. Hence it appears as the ship increases in E. lon- 

 gitude from 37° W., the variation of the compass increases W., but 

 to what extent I believe is not determined. 



Should these observations be worthy of insertion in your scienti- 

 fic Journal, they may lead to a completion of facts that would highly 

 benefit the science of navigation. 



I am, Gentlemen, yours, &c. 

 Bedford, July 8, 1829. W. H. White, H.M.C.S. 



Latitude. 



49° 30' N. 



10 S. 



21 00 S. 



40 00 S. 



Latitude. 



36° 30' S. 



21 30 S. 



20 N. 



49 40 N. 



ACTIVE MOLECULES IN ORGANIC AND INORGANIC BODIES. 



The peculiar and apparently inherent motion of these molecules 

 discovered .some time since by R. Brown, Esq. F.R.S.,* excites an 

 increased interest in consctjuence of the difficulty of accounting for 

 it satisfactorily. Mr. Holland, who lias for some time closely ap- 

 plied himself to microscopic researches, has found that the motion 

 continues equally vivid, when the liquid containing the molecules 

 * See I'hil. Mair. and Annals, N.S. vol. iv. p. KJl. 



N.S. Vol. G. No. 32. Aiiir. 1829. X Js 



