33 General Sabine — Note on Meteorological Correspondence, [Mar, 8^ 



respecting ohservations to he made at sea^ and ohservations to be made on 

 land', the immediate bearing of the one, and the contingent and eventual 

 bearing of the other. Their reply consequently bore chiefly on points to 

 be investigated by marine observations, — under the several heads of baro- 

 metric variations ; of those of the dry air and of aqueous vapour ; of the 

 mean temperature of the air ; of the temperature of the sea, and investiga- 

 tions regarding currents ; of storm_s and gales ; thunderstorms ; auroras 

 and falling stars ; and charts of the magnetic variation. (Proc. Roy. Soc, 

 vol. vii. pp. 342-361.) 



These were treated of in their generality, as subjects of investigation to 

 be made (in the words of the Board of Trade) " at sea in all parts of the 

 globe." Nor was the contingency of observations to be made on land upon 

 an extended scale, " which may hereafter be made and discussed in the 

 same office," overlooked; and to enable the Royal Society to be more 

 fully prepared, and to be ready "to provide for the contingency " whenever 

 it should present itself, the President and Council put themselves in com- 

 munication with several of their foreign members who were known as dis- 

 tinguished cultivators of meteorological science, — having always in view 

 the possibility that, when the occasion should occur, they might be 

 prepared to offer such suggestions as might facilitate the purpose which 

 had been deemed so desirable by Her Majesty's Government in the pre- 

 ceding year. The chief difficulty which had then presented itself had 

 been the desire shown by the meteorologists of the different European 

 States to adhere to the instruments, and more particularly to the hours 

 of observation, to which they had been accustomed. The hours had been 

 selected partly on grounds of convenience, and partly in the belief that 

 they were those best suited to receive the corrections required in different 

 localities for diurnal and casual variations. The most hopeful way of sur- 

 mounting the difficulties in question would obviously be the introduc- 

 tion of instruments which should be continuously self-recording ; such in- 

 struments would in addition supply the exact instants of the maxima and 

 minima of the different phenomena — points greatly required in the discus- 

 sion of the laws of extensive atmospherical disturbances. At the epoch of 

 the Cambridge Congress in 1 845 it was understood that no perfectly reli- 

 able instruments for continuous record were in use amongst the continental 

 observers. The self-recording instruments of M. Kreil, employed at the 

 observatories of Prague, Senftenberg, Vienna, and Munich, and which had 

 also been in use for many months at the Kew Observatory, were not conti- 

 nuously self-recording, and were also, in the opinion of many, not altogether 

 free from objections. The construction of instruments both in magnetism 

 and meteorology which should serve this important purpose and at the same 

 time be free from causes of error in other ways, had been a cherished object 

 of the Committee of the Eew Observatory from the commencement of that 

 institution. The advance which had been accomplished at a very early 

 period may perhaps best be stated in the following extract from the fourth 



