4 REMARKS tJPOfc METEOROLOGY* 



the heaviest falls of rain, and in summer, by a close, op* 

 pressive state of the air, and thunder. The 7th was also 

 a negative day, the barometer fell still lower, there were 

 large thunder clouds at noon, and lightning in the evening. 



Indications. -A different constitution of the atmosphere, however, now 

 took place, it became dissolving, the barometer began to 

 rise, and continued to rise with occasional interruptions for 

 several days. This change of constitution, the commence- 



x meat of a rise in the barometer, and the arc of the follow- 



ing morning, rendered it probable, that a complete change 

 of wind was at hand, and it accordingly took place in the 

 afternoon. The 9th was a different kind of day from any 

 that we had had since the beginning of the month ; 1 deno- 



Sour day. minate it a sour day, a phrase employed by landscape 

 painters, expressive of that state of the atmosphere, when 

 the whole face of nature appears chilled and gloomy. The 

 NW current was hastily tilling up the partial vacuum that 

 had taken place during the low state of the barometer, and 

 being deficient in caloric, it produced that large body of 

 clouds, which gave the peculiar character to the day. By 

 S haded clouds, the term shaded clouds I mean to designate the appearance 

 which the heavens occasionally present, where the clouds are 

 formed into rounded masses of greater or less extent, one 

 side of which is very much darker than the other side, in 

 the same manner that a solid globe is affected by the light 

 Piled clouds, shining upon it. By piled clouds is meant that state m 

 which s part of the horizon is occupied by a quantity of 

 large rounded clouds, which appear as if they were heaped 

 one upon another. 



In dications of The barometer had now attained nearly its average ele- 



u.isetiled wea- vat i orjj b ut tne c0 ]dness of the air, and the peculiar appear- 

 ance of the clouds, pretty certainly indicated, that the at" 

 rnosphere was not in a settled state. If, after the influx of 

 a cold current from the NW, the temperature of which is 

 . too low to keep its water in solution, the wind passes into 

 a sonheily noint, rain almost alwuys ensues, and the morn- 

 ing of the 10th exhibited a good specimen of the manner 

 in which ti is operation is performed. In the early part it 

 was Lri c ht > clear, and calm; but clouds soon began to form, 

 which rapidly increased in bulk, and after some time were 



