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272 



METEOROLOGY, 



[Sect. IX. 



By any Due, howerer, desirous 



of paying such parti- 

 cular attention to this branch of science as to entitle 

 him to the name of a meteorologist, a three-hourly 

 register— "yiz,5 for the hours 3, 6, 9, a.m., noon ; 3, C\ 9, 

 P.M., midnight — ought to be kept ; and in voyages of 

 discovery, where scientific observation is a prominent 

 feature, the register ought to be enlarged, so as to 

 take in every odd hour of the twenty-four; thus in- 

 cluding, without interpolation^ the six-hourly or standard 



series. 



8. Hourly observations should be made throughout the 

 twenty-four hours on the 21st of each month (except 



when that dav fall" 



on a Sunday, and then on the 

 Monday following), commencing with G a.m., and ending 



at 6 A.M. on the subsequent day, so as to make a series 

 of twenty-five observations. At all events, if this cannot 

 be done monthly, it ought not to be omitted in March, 

 June, September, and December. Tliese are called 



" term observations/' If any remarkable progressive 

 rise or fall of the barometer be observed to pervade this 

 series, it will be well to continue it until the maximum 

 or minimum is clearly attained, with a view to comparison 

 with other similar series elsewhere obtained, and thus to 

 mark the progress of the aerial wave effective in pro- 

 ducing the cliftnge. These term observations should be 



separately registered under that head. 



9 J Occasional hourly series of observations may be 

 made with advantage under several circumstances, as, for 

 instance — Istly. "When becalmed for any length of time, 

 aspecially when near the Equator, with a view to deter- 

 mining the laws and epochal hours of diurnal periodicity. 



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