SCHULTZENSTEIN — NUTRITIVE CONSTITUENTS OE WATER. 120 



unmanured coffee-plantations of Java last about the same time. 

 According to Junghuhn, those on the terraces of Tjisondari, 

 planted in 1804, had grown quite wild in 1846*, and yielded very 

 little fruit, whereas recent plantations, made since 1836, were so 

 luxuriant that not a sunbeam could reach the earth. The richest 

 soil of Texas is exhausted in twenty years ; the poorer in from 

 eight to ten. This exhaustion depends not upon the exhaustion 

 of ammonia, as asserted by Liebig and Boussingault, since, accord- 

 ing to the observations of Baumhauer and Krocker, the contents 

 of the soil in ammonia without any manure are far larger than 

 could be the case were it exhausted by the growing plants ; besides, 

 ammonia, according to the observations of Kuhlmann, is naturally 

 reproduced in the soil itself. The exhaustion of the soil depends 

 rather on the exhaustion of the humus ; and from this arises the 

 possibility of restoring its fertility by means of mouldering humific 

 dung. But where no manure is used, fertility is restored after 

 many years by the growth and decomposition of hardy weeds 

 which are supported by the moist innutritious soil. "We find, 

 according to Junghuhn, in Sumatra and Java abandoned planta- 

 tions turning into Allang-fields (tracts overrun with species of 

 Saccharum), while the inhabitants avail themselves of new plots 

 of forest-ground. The effect of fallowing is nothing more than 

 that of dressing ground with green weeds, which live on the water 

 of the soil (which is poor in nutritious matter), and then form 

 "humus by their decomposition. The process which favours the 

 nourishment of plants is the process of decomposition. 



The assumption of Liebig, in favour of the carbonic-acid theory, 

 that every acre of land, whether it be meadow or field, produces 

 on an average 20 cwt. of dry vegetable matter, either as hay, 

 wood, clover, corn, or tubers, rests upon entire ignorance of the 

 experience of horticulture and agriculture, and is as wrong as the 

 imperfect observations of Darwin, according to which tropical 

 plants grow from pure sand by means of the air. Such notions 

 can only lead to error in practice, and act injuriously on cultiva- 

 tion if it is conducted in accordance with such theories. All ex- 

 periments on the fertility or sterility of soils, on the restoration 

 of fertility by means of different kinds of manure, on the different 

 produce of woods, meadows, fields, and gardens, are useless in the 

 face of such assumptions ; we may as well give up speaking of 

 fruitful and barren land. The reckonings of pounds and hundred- 



* Literally had been converted into Allang fields, a term explained below. 

 VOL. I. K 



