378 Meteorological Observations, 



curred within the memory of the oldest inhabitants. The snow 

 Was excessively drifted ; its average depth being about two feet. 

 The storm extended beyond the AUeghanies, but was there un- 

 attended with wind ; so that the snow fell calmly to the depth of 

 near three feet. After much severe cold, and several other storms 

 of snow and rain, the winter quietly broke up towards the latter 

 end of February. The navigation of the Christiana creek, and 

 of the Delavi^are river, near Philadelphia, was closed, or ren- 

 dered impracticable by ice, from the 12th of January, to the 

 3d of March — a period of seven weeks. 



The spring of 1831 was rather forward, and generally mild. 

 In the second week of April, however, several severe frosts oc- 

 curred, which injured much of the earlier fruit, then in bloom. 

 A good deal of rain fell in March and April ; but in May, there 

 was only one rain of consequence, and that one not very heavy. 

 The month of May was, of course, very dry, so as to injure mate- 

 rially some of the crops. The few^ last days were unseasonably hot. 



After the middle of June, the summer of 1831 was remarkable 

 for damp weather, and excessive rains, which extended over a 

 great part of the United States. The grass crops had been in- 

 jured by drought ; and now the crops of grain were very much 

 damaged by wet. So moist was the atmosphere, that the " dry- 

 goods," of store-keepers, became mouldy on the shelves, in many 

 instances. Two feet of rain fell in July and August. There was 

 no hot weather, though it was often oppressive, on account of 

 the moisture which loaded the atmosphere. In the third week 

 of August, a dense haze obscured the sky, imparting a pecuhar 

 colour to the sun and moon — a yellowish green tinge. From the 

 beginning of July to the termination of the year, the air was 

 scarcely clear of a haziness for an hour at a time. It appeared to 

 have a close connexion with the tendency to produce clouds, which 

 was observed at the same time to exist in the aerial laboratory 

 of nature. Doubtless its cause must be referred to the precipita- 

 tion of vapour. The ruddy haze of Indian summer is a phenome- 

 non very analagous ; but when we consider the vast quantity of 

 vegetable exhalations which must result, at this season, from the 

 decomposition of plants, and the desiccation of the foliage of the 

 immense American forests, we cannot but grant to the effluvia 

 of decaying vegetation, some agency in the formation of the haze 

 of our autumnal sky. 



