Meteorological Observations. 335 



them in practice, only observing to make the extvemt; obscrva- 

 tion3 of each day equidistant from the middle one. ' 



At the same time it will be borne in mind, that in what 

 concerns the great Meteorological questions on which the most 

 interesting features of the subject depend, the night is quite as 

 important as the day, and has hitherto been far too much 

 neglected. To any one therefore who may feel disposed to 

 enter more zealously into the subject, and will not consider 

 some personal inconvenience ill undergone for the sake of 

 affording data of a peculiarly valuable description, this Com- 

 mittee would most earnestly recommend the adoption, in 

 preference to all others, of the quaternary division of the 

 24 hours as followed at the Royal Observatory above alluded 

 to. And they leave it to the consideration of the Council, 

 whether the keeping and transmission of registers on this 

 principle might not advantageously be distinguished by some 

 nonorarv reward, as that of a Medal for instance, should the 

 funds of the Institution admit of it. 



With a view, however, to the better determining the laws 

 of the diurnal changes taking place in the atmosphere, and to 

 the obtaining a knowledge of the correspondence of its move- 

 ments and afiections over great regions of the earth's surface, 

 or even over the whole globe, the Committee have resolved 

 to recommend, that four days in each year should hence- 

 forward be especially set apart by Meteorologists in every part 

 of the world, and devoted to a most scrupulous and accurate 

 registry of the state of the Barometer and Thermometer ; the 

 direction and force of the Wind ; the quantity, character, and 

 diUribution of Clouds ; and every other particular of weather, 

 throughout the whole twenty-four hours of those days, and the 

 adjoining six hours of the days preceding and following.* The 

 days they have been induced to fix on and recommend for 

 these observations are, the 21st of March, the 21st .June, the 

 2l3t September, and the 21st December, being those, or im- 

 mediately adjoining to those of the Equinoxes and Solstices, 

 in which the Solar influence is either stationary or in a state 

 0^ most rapid variation. Bi't should nn'j one of those 1\st 

 diysfill on Suu'lu'j, ihni it will he vr.derstood Hi it Ih" oliSf-rva- 

 tior.snre to be dcfrrrfd till the next dty, the 22d. The obser- 



• Tiiis is necessary by reason of the want of eoiiic id- nee of Ifw daij in 

 difTereiit paits of tiie globe, arising froin difference of longitud''. la 

 order to obtain a complete corn spondence of observation for 2-1 suc- 

 cessive liours over the whole (jlobe, it must be lal-en into iiccoinit that 

 oppo.siie longitudes (iiffcr 12 hour; in tlieir retkoninR of time. Hy the 

 strrangement in the text the wliole of the aslronomical day (from noon to 

 noon) is embraced in each series, and no observer i.s requiicd to watrh 

 two nights in succession. 



