HORARY VARIATIONS OF THE BAROMETER 



417 



From these differences it will be seen that, even for the overcast and cloudy 

 days, which show the slightest disparities between the maxima, as might readily 

 be foreseen from the explanation which we have given of the phenomenon of the 

 diurnal period, these disparities still exceed by much the three-tenths of a milli- 

 metre to which we were led by our supposition of a stratum of two millimetres 

 of water undergoing conversion into vapor, and conversely. 



The number of days to which our calculations were extended was but 244 ; 

 the rest of the year was left out of view, because the 121 days of which it con- 

 "isted found no well-defined place in the categories we had adopted. 



Tlie researches which follow comprij>e the 365 days of the year, being dis- 

 tributed in the classification according to the direction of the wind : 



'Winds. 



NNW V?"" (liv<? ^ Mean height of the maximum of 9 o'clock of the morning 7C1. 40 



NNE > / Mean height of the maximum of 9 o'clock of the evening 7G1. 36 



Difference 0.04 



Wind. 



KP \ ^1 ^ 5 Mean height at 9 in the morning 762. 36 



■^' 5 '^' "*y^-^Mean hdght at 9 in the evening 761.13 



Difference '. ].23 



Winds. 



T?\n? K'xc\ ^ ) Mean height at 9 in the morning 758.29 



ESe" t ^ J Mean height at 9 in the evening 757.18 



Difference 1.11 



Wind. 



op \ ,n I 5 Mean height at 9 in the morning 753.59 



oi!.. ^ vi, aays. ^ ^^^^^ \^e:\%\xi at 9 in the evening 752. 48 



Difference 1. 11 



Winds. 



s'sE >ri (lavs 5 Mean height at 9 in the morning 755. 41 



S S\V 1 / Mean height at 9 in the evening 753. 27 



Difference 2.14 



Wind. 



QW \ c\ ^ 5 Mean height at 9 in the morning 756.24 



ow. ^ Di aays. ^ Mean height at 9 in the evening 754.72 



Difference 1,52 



Winds. 



W ) ( 



\v'ci\v Crq 1 ) Mean height at 9 in the morning 756.69 



W NW S f *^®^" ^^'^^'^ ^'^ "^ ^° the evening 756. 24 



Difference 0. 45 



Wind. 



vw ^41/1 5 Mean height at 9 in the morning 7.59.10 



iM vv. ^ 41 aays. ^ ^^^^^ \^^\^\^i at 9 in the evening 759. 02 



Difference 0.08 



The preceding figures impart their instruction. We confine ourselves at 

 present to the remark, already made in reference to the distribution of days ac- 

 cording to the state of the sky. tliat the difference of the morning and evening 

 maximum is always in the same direction, and that, if we except the two cases 

 27 s 66 



