136 Observations on Liehig^s " Organic Chemistry ^ 



whole bones ? The fibres will cluster in the same way round a 

 piece of freestone, limestone, or potsherd. Though the presence 

 of ammonia around all the organs of plants, and in many of 

 their products, leads us to infer its necessity; yet it is, perhaps, 

 too much, to say that every pound of ammonia should produce 

 exactly a corresponding proportional increase in corn. Allowing 

 ammonia to have all the benefits claimed for it, we must have 

 the other constituents likewise, and must take into account the 

 structure of the leaves and other elaborating organs, in which 

 some plants possess much more power than others ; also the 

 variable quantities of light and heat, assisting and stimulaiing 

 those powers. There is some limit also to all these, however 

 far we may be from it yet, in agriculture and horticulture ; and 

 if we draw too much on these powers, as in over-fruiting, it 

 may be only to hasten the termination : all the food in the 

 world, though full of nitrogen, will not produce an indefinite 

 increase on the size either of plants or animals ; it is, perhaps, 

 necessary to notice this, to prevent our being too sanguine. 



Some of your readers, as Mr. Main, will be more able to give 

 information about Chinese operations. In a population so dense, 

 and where labour is so cheap, animals are less needed, and, the 

 ground being better pulverised and weeded, the crops will be 

 greater. The proper pulverisation of the ground, at proper 

 seasons, keeps it open, and admits both heat and moisture 

 more freely, as also the carbonic acid and ammonia of the at- 

 mosphere ; and, where it is broke into small pieces, the confined 

 air retains heat, moisture, and the gases more perfectly, the 

 small pieces of soil acting by capillary attraction ; the heat and 

 moisture on ground well pulverised are, without the aid of instru- 

 ments, perceptibly more than when it is not so. The great effects 

 of pulverisation and attention to the other requisites of cropping 

 have been frequently pointed out in this and other magazines ; 

 in the allotments assigned to cottagers, the produce on which is 

 many times that of ordinary cultivation, and in so populous a 

 country as China, this may have great effect. Many of the im- 

 provements in the manufactories of porcelain ware, silk, dyeing, 

 &c., were the results of practical application, discovered by ac- 

 cident, and kept for some time as secrets, though they have been 

 vastly improved on, and many new discoveries made by science. 



In what the professor says about the likelihood of uric acid 

 being soluble and absorbed, and the nitrogen it contains converted 

 into ammonia, we may be led to wonder if the small quantity of 

 nitrogen soluble in water (Dr. Thomson says, ]^ to 4 per cent) 

 may not be taken up by the roots and assimilated. It forms am- 

 monia most readily when newly set free; but the living plant 

 possesses more powers of transformation than we yet can define. 

 At p. 154<., it seems probable that the phosphates needed will 



