2 THE CANADIAN NATURALIST. [Feb. 



meteoric waters hold in solution, besides nitrogen, oxygen, car- 

 bonic acid, ammonia, and nitrous compounds, small quantities 

 of solid matters wbich were previously suspended in the form of 

 dust in the atmosphere. After falling to the earth, these same 

 waters become still farther impregnated with foreign elements of 

 very variable nature, according to the conditions of the surface on 

 which they fall. 



§ 2. Atmospheric waters coming in contact with decaying 

 vegetable matters at the earth's surface, take from them two 

 classes of soluble ingredients, organic and inorganic. The waters 

 of many streams and rivers are colored brown with dissolved 

 organic matter, and yield, when evaporated to dryness, colored 

 residues, which carbonize by heat. This organic substance, in 

 some cases at least, is azotized, and similar, if not identical, in 

 composition and properties with the apocrenic acid of Berzelius. 

 The decaying vegetation, at the same time that it yields a portion 

 of its organic matter in a soluble form, parts with the mineral 

 or cinereal elements which it had removed from the soil during 

 life. The salts of potassium, calcium, and magnesium, the silica 

 and phosphates, which are so essential to the growing plant, are 

 liberated during the process of decay ; and hence we find these 

 elements almost wanting in peat and coal. See on this point the 

 analyses by Vohl of peat, peat-moss, and the soluble matters set 

 free during its decay. Ann. der Chem. und Pharm., cix, 185, 

 cited in Rep. Chim. Appliquee, i, 289. Also Liebig, analysis of 

 bo^-water ; Letters on Modern Agriculture, p. 44 ; and in the 

 second part of this paper the analysis of the waters of the 

 Ottawa river. 



§ 3. At the same time an important change is effected in the 

 caseous contents of the atmospheric waters. The oxygen which 

 they hold in solution is absorbed by the decaying organic matter, 

 and replaced by carbonic acid ; while any nitrates or nitrites which 

 may be present are by the same means reduced to the state of 

 ammonia (Kuhlmann). By thus losing oxygen, and taking up a 

 readily oxydizable organic matter, these waters become reducing 

 instead of oxydizing media in their farther progress. 



§ 4. We have thus far considered the precipitated atmospheric 

 waters as remaining at the earth's surface ; but a great portion of 

 them sooner or later in their course, come upon permeable strata, 

 by which they are absorbed, and in their subterranean circulation 

 undergo important changes. The effect of ordinary argillaceous 



