USES. The ashes of sea-plants are a common source of bromine and iodine, and the ashes of animal bodies form a source of phosphorus. But the commercial value of ashes depends mainly on their use: (1) as a source of alkali (pearl-ash, potashes, etc.), and (2) as a fertilizer. The fer tilizing value of ashes is due to the fact that they contain all of the mineral constituents re quired by plants, especially potash, and that largely in one of the most desirable forms—viz., as potassium carbonate. The following three classes of ashes are the most important for agricultural purposes: (1) Wood ashes from household fires, furnaces, etc.; (2) cotton-hull ashes, resulting from the uses of cotton hulls as fuel under boilers, etc., in the cotton-growing regions; and (3) lime-kiln ashes, which are a mixture of more or less lime with the ashes of the fuel used in the kilns.
Woor) ASHES. Wood ashes were formerly the almost exclusive source of potash for fertilizing purposes. They have, however, been very largely replaced by the German potash salts. At the present time the supply of wood ashes is limited on account of the general substitution of coal for wood as fuel. Canada is the main com mercial source of supply in America. The ashes are collected from house to house and stored in structures built for their reception (asheries). When first collected they are said to weigh from 34 to 40 pounds per bushel ; but when stored they undergo a heating and sweating process which disintegrates the particles of charcoal and causes the ashes to shrink about one-fifth in the weight per bushel increasing from 40 to 48 pounds. Dealers estimate that it requires about 30 cords of hardwood to make one ton of ashes.
The composition of wood ashes varies with the kind of wood, the intensity of the fire, the pro portion of impurities and unburned material (charcoal), and the care in storage. The hard woods yield ashes richer in potash than those of the soft woods. In intense fires, some potash
is lost by volatilization. Pure ashes carefully prepared from hard woods have been found to contain more than 17 per cent. of potash ; those from soft woods almost 10 per cent., besides about 2 per cent. of phosphoric acid. No such ashes are found on the market. In several hundred analyses of samples of commercial, indeached ashes, there was found, on an average, about 5 per cent. of potash, 1.5 per cent. of phosphoric acid, and 30-35 per cent. of lime. This inferiority of the commercial product may result from un avoidable causes, or it may be partly due to adulteration with leached ashes, coal ashes, soil, etc. In any case, the great variability of the product emphasizes the importance of purchasing ashes only on a guaranty of composition. Al though the value of ashes as a fertilizer depends primarily upon the potash they contain. and al though they may be expected to give the best results on soils and crops especially demanding potash, still their fertilizing action is not en tirely due to the potash. The small amount of phosphoric acid Avid eh they contain is not with out fertilizing value, and the lime, which is present to the extent of 600 to 700 pounds per ton (of 2000 pounds), is of great value in im proving the texture and in ef irrecting the acidity of soils, besides supplying an element which is defieient in many soils.
Ashes which have been subjected to leaching show a reduced percentage of potash and an in creased percentage of moisture. The average composition of such ashes, as shown by a large number of analyses, is as follows: Moisture. 30 per cent.; potash, 1.3 per cent.; phosphoric acid, 1.5 per cent.; lime, per cent. The fer tilizing action of leached ashes is due very large ly to their favorable physical effects on the soil, which are brought about mainly by the lime present.