1820.] Dr. Buniej/'sMcleoiologicalJournalkeplatGosport. 435 



and wind ; but the stratus and citmulus generally indicate fair 

 weather for the time of tlieir appearance. The cumnlofitratua^ 

 even by inosculation, seldom passes to a nimhus, or rain cloud, 

 unless an extensive cirrus should happen to unite with it in its 

 descent. The cumulus, whose appearance is confined to the day, 

 is formed by a collection of vapours rising out of marshes, 

 rivers, Sec. ; it generally rises in an hemispheric form, moves in 

 the direction of the wind, and often evaporates perceptibly after 

 sunset in calm weather. It is probable that the nascent curuuhf^ 

 is sometimes formed by the rarefaction of the stratus in fair 

 weather. The lofty cumulus too has often been seen to transform 

 itself into a cirrocumulus. The cirrostiat us is formed by descend- 

 ing cirrus, or cirrocumulus, and sometimes comes down so low 

 as to sweep the surrounding hills : when stationary and attenu- 

 ated, it often resolves into dew after sunset. Such is our short 

 but practical view of the nomenclature of clouds. 



Weather. — The most remarkable difference of the two vears' 

 results under this head is in the number of completely overcast 

 days and nights, being 28 more this year than last; and the 

 clear or cloudless days and nights are eight less. Here it is 

 necessary to e.vplain the method by which the exact number of 

 days, under the respective divisions of weather, was ascertained. 

 It was done thus : if a cloudless day happened, and the sky was 

 not clear, or free from clouds at night, only half the dav was 

 accounted for as being clear ; the same regard to time was paid 

 to the continuance of rain, &c. If the day happened to be fair, 

 with sunshine and clouds, and the sky overcast at night, the 

 time was equally divided under those heads. 



Atmosplieric Plienouicna. — The most striking difference in the 

 results of the atmoi-^htnc phenomena for the last two years, is in 

 the number of meteors (some of them of a large size) ; of 121, 

 no less than 95 appeared in the evenings of July, August, and 

 September, the three hottest months in this year. It may, 

 therefore, be inferred, that they are generated by heat in an 

 atmosphere highly charg^ed with electric matter. There is, 

 however, a material diflerence in the quality of meteors, which 

 may be determined chiefly by their colours, apparent densities, 

 and altitudes. 



Evaporation. — The quantity evaporated this year is not so 

 great as it was last by 1 ^^ inches ; nor does it amount to sa 

 much as the depth of rain, &c. by 2*07 inches :, consequently 

 the ground at the close of the vear must have been in a moist 



state 



Variation of the Mo'^netic Needle —From the mean of dailv 

 observations on the magnetic needle this year, it has been found 

 to decrease about 2' in its western course, compared with obser- 

 vations made last vear ; but whether this recession will be pro- 

 gressive is a ouestiou of no small importance, and which must be 



2i;2 



