290 Proceedings of the British Association, 



jected in curves. Nothing can exceed the clearness with which the 

 march of the diurnal changes is exhibited in these results ; and I sin- 

 cerely hope that means may be found for printing them in such a 

 form as may secure to them their permanent authority and value. 



Another discussion of the meteorological observations made at 

 sixty- nine stations at the equinoxes and solstices in the years 1835, 

 1836, 1837, and 1838, which have been reduced, and cynographed 

 with great care and delicacy by Mr. Birt, at the expense of the As- 

 sociation, forms the subject of a Report by Sir J. Herschel, [Athen. 

 No. 828,] in the volume of our Reports for the present year, and 

 may be considered as a prelude, on a small scale, of the species of 

 analysis which the results of the great system of observations now in 

 progress should hereafter undergo. The inferences which are drawn 

 from the examination of the changes of atmospheric pressure, with 

 more especial reference to the European group of stations only, are in 

 the highest degree instructive and valuable. 



The system of magnetic observatories was at first designed to con- 

 tinue for three years only, but was subsequently extended to the 1st 

 of January 1846 : for it was found that the first triennial period had 

 almost elapsed before the instruments were prepared, or the observers 

 instructed in their duties, or conveyed to their stations. The extent 

 also of co-operation increased beyond all previous expectation : six 

 observatories were established, under the zealous direction of M. 

 Kupffer, in different parts of the vast empire of Russia, — the only 

 country, let me add, which has established a permanent physical ob- 

 servatory. The American government instituted three others at 

 Boston, Philadelphia, and Washington ; two were established by 

 the East India Company at Simla and Sincapore ; from every part 

 of Europe, and even from Algiers, offers of co-operation were made. 

 But will the work, which has thus been undertaken with such 

 vast prospects, be accomplished before the termination of the second 

 triennial period? or is it not probable that the very discussion 

 of the observations will suggest new topics of inquiry, or more 

 delicate methods of observation ? If the march of the diurnal, month- 

 ly, and annual movements of the needle be sufficiently determined, 

 will its secular movements be equally well known ? In other 

 words, shall we have laid the foundations of the theory, which may 



