4 



T 





f 



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Sect. IX.] 



METEOROLOGY. 



'297 



^. 



iramterrupted, leaving to others to watch the phases of 

 the eclipse. The atmospheric circumstances should be 

 most carefully noted during the whole series. 



Thermometers fi 



The measure 



of terrestrial radiation is of no less importance to the 

 science of meteorology than that of solar radiation, but 

 no perfect instrument has yet been contrived for its deter- 

 mination. Valuable information, however, may be derived 

 from the daily register of the minimum nocturnal tem- 

 perature of a register spirit-thermometer, the bulb of 

 which is placed in the focus of a concave m.etaUie mirror, 

 turned towards the clear aspect of the sky, and screened 

 from currents. Such a thermometer may be read oflF and 

 registered at the regular hours by day as well as by night, 

 but it must be screened from sunshine, and a thermometer 



same 



Reqist^rs. 



To keep a m-eteorological register with due regularity^ 

 a skeleton form (No. 1) should be prepared, by ruling 

 broad sheSts of paper into columns destined for the 

 reception of the daily and hourly entries in tlieir uncor- 

 rected state, as read off or otherwise noted. This form 



may 



be most 



advantasjeouslv arranged in groups of 



columns, with general heading {A^ B, C, &c.) 



ticular sub-headings (a, b, c, 







as to class the 



ft 



entries in an order favourable to subsequent comparison 

 and reduction. Thus, the group A should carry the 



ire; C, Temperature oj 



Date : B. Press 



air; D, Moisture; E, Radiation.; F, Ternperatm 

 ivater ; G, Wind; H, Cloud; /, Weather; 



e 



f 





Rain 



o 3 



