ObservatioJis on Liehig's " Organic Chemistry T 117 



may help to restore it ; in the second and fourth, the effects 

 should be partly owing to the other elements of the cow manure 

 and leaves; and in the third, the wormwood might scourge in 

 other respect as well as potash. 



Plants do not impoverish soil in the direct ratio of the 

 bulk they produce. Privet and leek, which are very scourg- 

 ing crops, do not produce near so much bulk as poplars and 

 potatoes, which scourge it less ; they scourge more in the 

 ratio of the fibres of the root. Some plants seem not to 

 extract so much nourishment from their food, as we find some 

 animals will grow larger on much less food than others ; and this 

 also varies with the circumstances, as heat producing activity in 

 the lacteals, leaves, &c. : it is the quantity of food which plants 

 assimilate, not what they absorb, that increases bulk ; they will 

 have most excrement that assimilate least. Such things the 

 professor mio-ht not think worth noticing when advocating a 

 particular subject, such as this on alkalies ; but, when placed 

 together, they help to prevent our going to excess with our in- 

 ferences from data. Sea plants will grow inland, he continues, 

 if near salt-works ; and the urine and bones of men and animals 

 yield the phosphates of lime and magnesia necessary for the 

 grains they cultivate as grasses. Hence, these plants follow 

 human habitations, as some weeds which abound in ammonia are 

 found on dunghills. From these facts he infers that plants 

 will not succeed well, unless the phosphates, &c., needed are 

 present; and these will always produce more fertility than any- 

 other manure. In this country, bones have been reckoned more 

 beneficial to turnips than to any other crop; and yet the analysis 

 of turnips by Dr. Madden gives no phosphates at all. Perhaps 

 the animal matters, as gelatine, &c., in the unboiled bone furnish 

 food to the turnip, and the phosphates to the next crop of wheat. 

 There must be some relation between the food and the analysis 

 of the plant, the doctrine of plants producing elements them- 

 selves I think untenable ; but we have much yet to learn. 



From the capability of volatilising borax; from the salt in salt- 

 works being found deposited on glass fixed above the works, in 

 their atmosphere ; and from the air over the sea always con- 

 taining sufficient to i^ender a solution of nitrate of silver turbid ; 

 lie contends for the salts of plants being carried in the atmo- 

 spiiere. The carbonate of lime in the sea is only one part in 

 12,400, and yet supplies the myriads of mollusca and corals. 

 The iodine in fuci is collected from sea water, which contains 

 only one part in a million. Hence, the immense effects produced 

 from small quantities ; and, though the alkalies are contained in 

 the air in small quantities, great effects may ultimately be pro- 

 duced. The sea water contains more carbonic acid than fresh 

 water, and also contains ammonia. The sea being filled with 



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