Xliv REPORT — 1844. 



to no station but their own, and even with respect to it possessing no sufficient 

 continuity and system ; they have been for the most part desultory, indepen- 

 dent, and consequently worthless. It would be unjust however to the merits 

 of one of the most assiduous and useful of our members, Mr. Snow Harris, 

 if I did not call your attention, in connection with this subject, to his Reports 

 (included in the Reports of our Twelfth Meeting) on the meteorological obser- 

 vations at Plymouth made by him, or under his superintendence with the aid of 

 a very moderate expenditure of the funds of the Association. They compre- 

 hend observations of the thermometer at every hour of the day and night 

 during ten years, and of the barometer and anemometer during five years, 

 carefully reduced and tabulated, and their mean results cymograjjked or pro- 

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

 the diurnal changes are exhibited in these results, and I sincerely hope that 

 means may be found for printing them in such a form as may secure to them 

 their permanent authority ar;d 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 cymographed with great care by Mr. Birt, 

 at the expense of the Association, forms the subject of a Report by Sir John 

 Herschel in the volume of our Reports for the present year, and maybe con- 

 sidered 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 Euro- 

 pean group of stations only, are in the highest degree instructive and valuable. 



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

 veyed to their stations ; the extent also of cooperation increased beyond all 

 previous expectation. Six observatories were established, under the zealous 

 direction of M. Kupfter, in different parts of the vast empire of Russia, the 

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

 vatory. The American government instituted three others, at Boston, Phila- 

 delphia and Washington ; two were established by the East India Company, 

 at Simla and Sincapore ; from every part of Eurojie, and even from Algiers, 

 offers of cooperation 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, monthly 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 foundation of a theory, 

 which may even imperfectly approximate to the theory of gravitation in the 

 accuracy and universality of its predictions? It is with reference to these 

 important questions, and the expediency of continuing the observatories for 

 another triennial term, that M. KupfTer has addressed a letter to Colonel 

 Sabine, suggesting the propriety of summoning a magnetic congress, to be 

 held at the next Meeting of the British Association, and at which himself, 

 Gauss, Humboldt, Plana, Hansteen, Arago, Lamont, Kreil, Bache, Quetelet, 

 and all other persons who had taken a leading part in conducting, organizing, 

 or forwarding these observations should be invited to attend. 



This proposal has been for some time under the anxious consideration ot 



