ADDRESS. 



xliii 



greater resemblance to each other than was indicated by that primary and ne- 

 cessarily imperfect essay of tlie theory. 



The range of Sir James Ross's observations extends over more than three- 

 fourths of the navigable parts of the southern seas, and you will learn with 

 pleasure that one of his most efficient officers, Lieut. Moore, has been des- 

 patched from the Cape with a vessel under his command to complete the 

 survey of the remainder. 



Nothing could exhibit in a more striking light the completeness of the 

 organization and discipline of the system of magnetic observatories than 

 the observations of the great magnetic storm of the 25th of September 1841 ; 

 it was an event for which no preparation could be made, and whicii no ex- 

 isting theory could predict ; yet so vigilant and unremitting was the watch 

 which was kept, that we find it observed through nearly its whole extent, 

 and its leading circumstances recorded at Greenwich, in many of the obser- 

 vatories on the continent of Europe, at Toronto, St. Helena, the Cape, Ho- 

 barton, and at Trevandrum in Travancore ; for even the mediatized princes 

 of the East have established observatories as not an unbecoming appendage 

 to the splendour of their courts. Some of the observations of this remark- 

 able phaenomenon, and of many others (twenty-seven in number) of a similar 

 nature, have been discussed with great care and detail by Colonel Sabine, and 

 lead to very remarkable conclusions. They are not absolutely simultaneous at 

 distant stations, nor do they present even the same succession of phases as at 

 first anticipated ; and it is the disturbances of the higher order only which 

 can be considered as universal. They are modified by season as well as by 

 place; the influence of winter in one hemisphere and of summer in the other, 

 on the same storm, being clearly distinguishable from each other. The simul- 

 taneous movements in Europe and America have been observed to take place 

 sometimes in opposite and sometimes in the same direction, as if the disturb- 

 ing cause was in one case situated between these continents, and in the other 

 not; and we may reasonably expect, when our observatories are furnished 

 with magnetometers of sufficient sensibility to indicate instantaneously the 

 effects of disturbing causes, that the localities in which they originate may be 

 approximately determined. These are very remarkable conclusions, and well 

 calculated to show the advantages of combined observations. In such inqui- 

 ries, observations in a single and independent locality, however carefully they 

 may be made, are absolutely valueless. 



The meteorological observations are made, in all these observatories, on the 

 same system and with equal care with those of magnetism ; they embrace the 

 mean quantities, diurnal and annual variations, of the temperature, of the 

 pressure of the atmosphere, of tlie tension of the aqueous vapour, of the di- 

 rection and force of the wind, with every extraordinary departure from the 

 normal condition of these elements, as well as of auroral and other phaenomena. 

 It would be premature to speak of the conclusions which are likely to be de- 

 duced from tliese observations, inasmuch as the reduction and comparison of 

 them, with the exception of those at Toronto and Greenwich, has hitherto 

 made little progress ; but they cannot fail to be highly important ; for it is 

 by the comparison of observations such as these, made with reference to a 

 definite system, with instruments constructed upon a common principle and 

 carefully compared with each other, and by such means alone, that the science 

 of meteorology can be not only advanced but founded. 



Our philosophical records have for the last century been deluged with me- 

 teorological observations ; but they have been made with instruments adapted 

 to no common principle, compared with no common standard, having reference 



