438 On the Periodic Change of Climate caused' by the Moon. 



during a lunar year would be the showing it by means of only 

 one hour of daily observation. It were best to take 9 a.m. for 

 that purpose ; for it gives nearly the mean annual temperature. 

 M. Quetelet has published (in 1867) a series of meteorological 

 observations made in Belgium at 9 a.m., reaching from 1839 

 to 1863 at Ghent, and from 1847 to 1863 at Liege. The 

 averages of annual temperatures and pressures are : — 









Difference. 





Difference. 



1838-43. 

 1843-48. 

 1848-53. 

 1853-57. 



Max. to mean. 

 Mean to min. 

 Min. to mean. 

 Mean to max. 



10-32 C. 

 10-53 „ 

 10-66 „ 

 10-50 „ 



+0-21 C. 

 +0-16 „ 



millims. 

 758-84 

 758-74 

 758-84 

 759-16 



millim. 

 -010 



-0-32 



The differences are less perceptible ; but they retain their signs, 

 as required by the law. 



The averages of annual temperatures and pressures at Liege. 



1848-52. 

 1852-57. 



Min. to mean. 

 Mean to max. 



10-980 C. 

 9-580 „ 



+ 1-400 C. 



millims. 

 75402 

 755-18 



millim. 

 -M6 



The averages of annual temperatures calculated by means of 

 three observations daily made at Elbing (Prussia). 



1829-33. 



1834-38. 



Min. to mean. 

 Mean to max. 



7-820 

 6-394 



+ 1-43 R. 



It follows that the periodical variations of temperature pro- 

 duced by the moon during half a lunar year is nearly 1°*2 R. 

 (average of the observations of Prague, Liege, and Elbing). 

 Besides, the variations of temperature and pressure are, during 

 half a lunar year, in a constant ratio one to another, as will be 

 perceived by the following data : — 



Prague. 







Differences of the average 



Of tempe- 

 rature, 



At. 



Of pressure, 



Ab. 



1848-52. 

 1852-57. 

 1857-62. 

 1862-66. 



7881 R. 

 6-922 „ 

 7-178 „ 

 8-402 „ 



329-003(P.l.) 

 329-280 „ 

 329-714 „ 



329-178 „ 



+0-959 R. 

 + 1-224 „ 



-0-277(P.l.) 

 -0-536 „ 



