236 TENTH ANNUAL REPORT OF 



tliey are dispersed or accumulated in* a special region of tlie heavens, 

 in the liorizon, at the zenith, &c. 



BAIiSr. 



It is necessary to note as accurately as possihle the hour at which 

 the rain begins and ends ; if it is a continued rain, or at intervals and 

 in showers; if it is general or only partial, preceded, followed, or ac- 

 companied by fogs ; the size of the drops and the force of the rain 

 should be also noted. For these different cases, the following desig- 

 nations may be adopted: 



Bainy, when the fall of some drops and the appearance of the wea- 

 ther is such as to indicate the approach of rain. 



Continued rain. 



Interrupted rain. 



Shower, which lasts not more than a quarter of an hour. 



General rain, which prevails over the whole extent of the horizon. 



Partial rain, which falls from the clouds that pass over only a small 

 extent of country. 



The force of the rain may be indicated by the following gradations : 



Drizzling rain, which falls in very small drops, almost like those of 

 mist. 



Slight or fine rain. 



Moderate rain. 



Heavy rain. 



Violent rain, heavy and strong pelting rain. 



The size of the drops seems to depend chiefly upon the height of the 

 clouds, and consequently upon the seasons and the circumstances of 

 the temperature. 



The snow. — The period of the first and last snow, the size of the 

 flakes, their forms. 



Sleet, which consists in small balls of snow, wh'iteand opaque, com- 

 monly without a crust of ice, like the opaque nucleus found within 

 hail-stones, falling more frequently in spring and in autumn. 



Frozen rain drops should be distinguished from the preceding forms ; 

 they make little balls of transparent ice. 



Hail. — Indicate the size and form of the hail-stones, the extent and 

 course of the phenomenon. 



THUNDER-STORMS. 



The time of beginning and ending of the storm jQust be indicated 

 as exactly as possible ; the point of the horizon whence it rises, the 

 direction of the clouds, of the wind and its variations, and, if pos- 

 sible, the quantity of rain before and during the storm ; of liail, &c.j 

 which falls , note if it passes over the place of the observation, or at 

 a distance ; if it is accom])anied, or not, with strong electrical detona- 

 tions and numerous lightnings. It will be well to ascertain the state 

 of the meteorological instruments during the storm^, especially of the 

 barometer and the thermometer. 



In the journal, the occurrence of a storm will be indicated in the 

 column of remarks merely by the letters Th St, with the hour when 



