1868.] 



President's Address. 



137 



rological department of the Board of Trade under its former management. 

 These latter, however, were only calculated for spaces of five degrees 

 square. In addition, some of the work left in an unfinished state by Ad- 

 miral Fitz Roy has been undertaken by the office at extra hours, and a 

 series of wind-tables for the Atlantic have been ordered to be printed. The 

 discussion of general meteorological information for the Pacific seaboard of 

 South America is in a state far advanced towards completion. 



3°. The system of telegraphic weather-intelligence, described in my last 

 year's anniversary address, has received a further development, and at 

 present the Drum signal is hoisted at 97 British stations, to convey the 

 intelligence of the existence of atmospherical disturbance in each case to 

 such ports as may appear to the central office to be reasonably liable to .be 

 affected by it. Similar intelligence has been telegraphed to Hamburg 

 since February 1868 ; and in the course of last month Herr von Freeden, 

 the Director of the newly established meteorological office in that city (the 

 Nord-deutsche Seewarte), has informed the London office that the harbour 

 authorities on the Elbe have resolved to hoist the Drum signal at Ham- 

 burg and Cuxhaven whenever intelligence implying probable danger shall 

 be received from London. In France also the ministry of the marine 

 has adopted, for the present at least, the practice of telegraphing facts and 

 not prophecies. 



In addition to the telegraphic communications already referred to, the 

 London Office sends, by special request, telegraphic intelligence of the 

 existence of a certain amount of difference of barometric pressure between 

 two stations within a defined area, to Mr. Eundell (Secretary of the Under- 

 writers' Association at Liverpool), and to the Dutch authorities. The in- 

 fluence which the distribution of atmospheric pressure exerts on the motion 

 of the air has been much dwelt upon by Dr. Buys Ballot, of Utrecht, and a 

 rule has beeu propounded by him for inferring the coming direction of the 

 wind from simultaneous readings of the barometer at different places. In 

 order to lay the foundation of a systematic study of our weather, and, at 

 the same time, to test the truth of this rule, it has been the practice of our 

 meteorological office, for more than a year past, to prepare, and subject to 

 systematic discussion, daily charts of the meteorological condition over the 

 area embraced by the daily telegraphic reports which it receives, viz. the 

 British Islands and a portion of the nearer continental coasts. The results 

 of this investigation are on the whole encouraging, and favour the hope that 

 with a more extended experience a real, if slight, advance will have been 

 made in this most intricate but interesting inquiry. 



The magnificent but rare phenomenon of a total solar eclipse is not 

 more striking as a spectacle than interesting in a scientific point of view, 

 from the precious opportunity it affords of gathering information, then 

 only to be obtained, which bears on the constitution of our great lumi- 

 nary. The corona which surrounds the dark body of the moon must have 



l2 



