Meteorological Observations. 333 



itself a sufficient indication whether rain has fallen in the night 

 or no. However, there are nsually good reasons for decision on 

 this ]ioint from other indications. Attention to the amount of 

 dew is very necessary, not only hccatisc the meteorological 

 questions involved are of a high degree of interest generally, 

 but because in arid climates ihe dews are of almost as much 

 imiioriance to the maintenance of vegetation as the rain. 



In stating the quantity of rain daily received in the jruage, 

 the height of the receiver above the soil should be mentioned, 

 experience having shown that the quantities of rain which 

 actually fail on a given area on the ground, and at a very 

 moderate height above it, often dilfer materially. In some 

 localities and circumstances, the rain-drops receive accession 

 from the air as they descend, in others they undergo partial 

 evaporation. The former is generally the case in cool moist 

 climates — the latter may be expected in this country. 



Of the Wind. 



The points most important to remark respecting the wind, are^ 



1st. Its average intensity and general direction during the 

 several portions of the day devoted to observation and registry. 



2ndly. The hours of the day or night when it commences to 

 blow from a calm, or subsides into one from a breeze. 



3rdly. The hours at which any remarkable changes of its 

 direction take place. 



4tlily. 'ihe course which it takes in veering, and the quarter 

 in which it ultimately settles. 



5thly. The usual course of periodical wmis, or such as 

 remarkably pre\ail during certain seasons, with the law of their 

 diurnal progress both as to direction and intensity — at what 

 hours and by what degrees they commence, attain their max- 

 imum, and subside, and through what points of the compass 

 tl.ey run in so doing. 



6thly. The existence of Crossing Currents at different heights 

 in the atmosphere, as indicated by the course of the clouds in 

 different strata. In ohser»iiig ihise, it is advisable to fix the 

 eye by some immoveable ohj ct, as some point of a tree or 

 building, the sim, or the moon, otherwise mistakes are apt to 

 arise. 



7ihly. The times of settin.r-in of remarkably hot, or cold 

 winds,— the quarters from which they come, and their courses, 

 as connected with Ihe progressive changes in their temperature. 



Sihly. The coiine\ion of rainy, cloudy, or fair weather, 

 with Ihe quarter from which the wind blows or lias blown, for 

 some time previous. 



9thly. The usual character of the winds as to moisture or 



