150 THE YEAK-BOOK OF AGRICULTURE. 



Nascent Manures. 



THE following article on the above subject has been published by Dr. David Stewart, 

 Chemist of the Maryland State Agricultural Society: ., 



Reasoning from analogy, all manures must be presented to the plant in the nascent state, 

 in order to their assimilation ; but a safer proposition, perhaps, would be, that many ele- 

 ments of plants, while they exist iu their normal or natural condition, are as perfectly unas- 

 similable, or as incapable of affording nourishment to them, as they are to animals. A 

 hundred illustrations of the law will at once occur to every intelligent mind ; and the facility 

 with which even inorganic compounds unite while in the nascent form is familiar to all. 

 Every molecule of matter, whether composed of compound or simple atoms, seems to have a 

 form of its own, and until it has assumed this form, or state of aggregation, it is in the 

 nascent state, or in an allotropic condition. While in this nascent state, its tendency to 

 unite with other bodies which have an affinity for it is wonderfully increased ; indeed, it is 

 often the only condition in which two substances will combine. Lime and magnesia, when 

 recently slaked, are capable of uniting more freely with other substances ; if, however, the 

 slaked lime or magnesia is kept for a long time, even although perfectly excluded from the 

 air, it will gradually assume the form of granules, and subsequently these molecules will 

 form crystals, or the lowest order of organism ; and these organisms seem to possess a de- 

 gree of resistance to external force analogous to the resistance of the higher organisms ; in- 

 deed, the more perfect crystals, of the same substance and in the same solution, will grow 

 and become more perfect at the expense of those which are irregular. Upon this principle, 

 the perfect crystals may be said to be approximating to the allotropic condition or nascent 

 state, while the perfect crystal is in the normal condition. 



It may be said that extent of surface is one of the causes of this, and a better illustration 

 is sand or quartz, which is perfectly insoluble in its natural or normal condition, however 

 fine the powder, even in some of the strongest acids. But sand or silica is frequently found 

 in the nascent condition, and then it dissolves readily in water ; moreover, it can be kept in 

 this condition for years ; but if heated to the temperature of 260, it assumes the normal 

 condition, and becomes perfectly insoluble even in acids ; whereas, before, it would dissolve 

 in acids, alkalies, or pure water. 



Lime and magnesia, while in the caustic state, are capable of converting sand into soluble 

 silica ; and this is perhaps one of the good effects of liming, especially when we consider 

 the remarkable influence that soluble silica exerts in absorbing ammoniacal manures. We 

 may also account thus for the crumbling of stable walls, the moist condition of old walls, 

 and especially those that are exposed to ammoniacal exhalations. Moreover, we have a 

 plausible mode of accounting for nitre-beds, and the remarkable value of old plaster ; also 

 the purifying influence of whitewashing, if it is done with caustic lime, and not with whiting 

 or carbonate of lime. Lime, while caustic and moist, in contact with sand, converts a small 

 part of the surface of the grains of sand from the insoluble to the soluble silica ; and this is 

 the reason why caustic lime is necessary to the formation of good mortar, as it is not (as is 

 almost universally supposed) a mere mechanical mixture of lime and sand, neither is it 

 grains of sand cemented together by the induration of lime ; but the actual solution of the 

 surface of the grains of sand produces a still more intimate union. 



Well, this soluble silica gradually absorbs from the atmosphere the ammonia, for which it 

 has a remarkable affinity ; and as ammonia is the vehicle of poisonous exhalations of dis- 

 ease, as well as the perfume of flowers, these exhalations are so concentrated upon the walls 

 of hospitals, that it sometimes becomes necessary to remove the plastering, in order to get 

 rid of erysipelas and other diseases. Nearly or quite all of the nitric acid of commerce was 

 no doubt originally derived from ammonia in the order above referred to ; for if my theory, 

 as above stated, is admitted, then every authority will sustain me in saying that old plaster 

 contains ammonia, and this ammonia is converted into nitric acid on the wall. Salts of 

 nitric acid can be seen by any one on the surface of old walls. Moreover, the leachings of 

 old walls have frequently been used in the manufacture of gunpowder, and old plaster 

 always enters into the composition of artificial nitre-beds. It will be readily admitted that 



