92 The Organic Matter of Soil. [August, 



ful serenity, and the sea fanned by gentle breezes, seemed pecu- 

 liarly inviting to the mariner and tempted him to the treacherous 

 main. But nothing was known of the thick smoky aspect so 

 peculiar to our Indian summer. The location of the region where 

 this phenomenon occurred, in a climate not subject to destructive 

 frosts, and in the midst of a vast extent of cultivated land, sufficiently 

 explains the reason of the serenity of the atmosphere. Many causes 

 conspire to render this bland, dusky season peculiar to America. 



The vast extent of timbered lands, and the nearly simultaneous 

 destruction of foliage over its northern portions by autumnal 

 frosts, and the remarkable difference between the temperatures of 

 winter and summer, with the rapid change from one to the other, 

 all conspire to produce, when considered a priori, such a season 

 as we realize in our Indian summer. 



That the smoky aspect of this period is caused by extensive 

 fires at the far west, or in other quarters, cannot be believed, as 

 such a cause does not annually exist to an extent sufficient to ac- 

 count for it. That smoke and opake particles from fire can be 

 wafted to a great distance, is sufficiently proved by the fact, that 

 in the summer of 1783 all Europe was overshadowed by a gloom 

 from the eruption of a volcano in Ireland. That such an event, 

 or even a common fire should occur periodically, and that too just 

 at the time when the elements are at rest, is too absurd to be en- 

 tertained. These hypotheses would not have been noticed, had 

 not arguments to sustain them been published in journals of repu- 

 table standing. That the atmosphere at this season contains or- 

 ganic matter in more than ordinary quantities, cannot be proved 

 without a delicate analysis; yet it seems extremely probable that 

 foreign matter should exist more then than at other times, and at 

 least so modify it that it should reflect more of the blue ray of the 

 solar spectrum than the other tints. 



THE ORGANIC MATTER OF SOIL. 



An allusion is made to the use of organic matter of the soil, on 

 page 40 of the July number. It is as follows: " Supplying, then, 

 the soil with decomposing organic matter, and several important 

 results follow; the rocks are dissolved and the plants may be sup- 

 plied with the necessary carbon, ammonia, and other essential in- 

 organic matter." The doctrine contained in this extract is im- 

 portant, and may be drawn out more in detail. The opinion has 

 generally prevailed that mould, or the black matter of soil, was 

 eminently useful. Many, and perhaps all, at one time entertained 



