AMERICAN GRASS. 



AMMONIA 



only one sowing is necessary, either at the end 

 of August, or beginning of September, for a 

 supply during winter and spring. It may be 

 sown broadcast, but the most preferable mode 

 is in drills nine inches apart. Water may be 

 given occasionally during dry weather, both 

 before and after the appearance of the plants. 

 If raised from broadcast sowings, the plants 

 are thinned to six inches apart; if in drihs, 

 only to three. In winter they require the 

 shelter of a little litter or other light covering ; 

 and to prevent them being injured by its pres- 

 sure, some twigs may be bent over the bed, or 

 some light bushy branches laid amongst them, 

 which will support it. The only cultivation 

 they require is to be kept clear of weeds. 



In gathering, the outside leaves only should 

 be stripped off, which enables successional 

 crops to become rapidty fit for use. When the 

 plants begin to run, their centres must be cut 

 away, which causes them to shoot afresh. For 

 the production of seed, a few of the strongest 

 plants raised from the first spring sowing are 

 left ungathered from. They llower in June or 

 July, and perfect their seed before the com- 

 mencement of autumn. (G. \V. Johnson's Kit- 

 cJien Gurdtn.} 



[This plant in America is commonly called 

 wild pepper-grass. It is frequent in fields and 

 on roadsides in the Middle States.] 



AMERICAN GRASS. A term sometimes 

 applied [in England] to a species of agrostis. 



AMMONIA. The name given by chemists 

 to the volatile alkali, from its being first pre- 

 pared in the East from camels' dung near to a 

 temple dedicated to Jupiter Ammon. It is 

 known in commerce under the name of harts- 

 horn, sal volatile, &c., and is prepared by the 

 dry or destructive distillation of animal sub- 

 stances. It is formed also most commonly 

 wherever animal substances undergo putre- 

 faction. It is composed of 



Hydrogen 



A/ote or nitrogen 



0-125 

 1-75 



Ammonia is usually produced in the state 

 of carbonate of ammonia, or united with car- 

 bonic acid gas, and in this state, or in fact in 

 combination with most other acids, it forms 

 salts, which possess peculiarly fertilizing pro- 

 perties. This alkali fulfils, there is little doubt, 

 a very important part in many organic ma- 

 nures. It is a very universally diffused sub- 

 stance, has been detected in rain-water and 

 even in snow, and there is little doubt but that 

 it exists, and prejudicially too, to the health of 

 the inhabitants, in the atmosphere of many 

 places crowded with animal life. (Liebig's 

 Or^'inic Chem. 76, 77.) Wherever this alkali 

 is detected in a substance, such as it commonly 

 is, for instance, in urine, gas-water, &c., the most 

 excellent effects may be anticipated to vegeta- 

 tion by its use. Fresh urine contains phosphate 

 of ammonia, muriate of ammonia, and lactate of 

 ammonia, and there is perhaps no fertilizer! 

 more powerful in its effects than this. 



[One of the most important discoveries bear- ' 

 ing upon agriculture perhaps ever made, is ' 

 that just promulgated by Liebig, of the exist- ' 

 er.ee in the atmosphere of ammonia. Davy 

 and other chemists of the highest celebrity had , 

 80 



analyzed the air collected from ,he most sicklv 

 locations where impurities might certainly be 

 expected to exist, but with their nicest tests 

 and best conducted experiments they tailed to 

 detect any essential difference in the composi 

 tion of the insalubrious air taken from the 

 deadly coast of Africa, and that collected from 

 the most elevated and healthy parts of Europe. 

 The analyses of the air of the different places 

 all gave the same proportions of the gaseous 

 constituents, namely, oxygen, nitrogen, and 

 carbonic acid. It was evident, therefore, that if 

 other matters, in addition to the gases named 

 and watery vapour, existed in the air, some 

 other means must be found to demonstrate their 

 presence ; and happily, the genius of Liebig 

 devised a plan by which this has been effected 

 so far as the presence of ammonia is con- 

 cerned. He knew that ammonia had a strong 

 affinity for water, by which it is promptly ab- 

 sorbed, and that although it could be diffused 

 through such a great bulk of air as to be 

 placed beyond the reach of chemical tests, it 

 might nevertheless be taken up by rain-water, 

 and washed down in sufficient quantity to be- 

 come apparent. Experiments made, in his 

 laboratory at Geissen, with the greatest care 

 and exactness, fully confirmed his views, and 

 placed the presence of ammonia in rain-water, 

 and consequently in the atmosphere, beyond a 

 doubt. It had hitherto escaped detection be- 

 cause no one thought of searching for it in the 

 same way. A single pound of rain-water con- 

 tains as much of the gas of ammonia, as is 

 diffused through 28,800 cubic feet of air, 

 namely, only one-fourth of a grain. 



"All the rain-water employed in this inquiry," 

 says Liebig, " was collected 600 paces south- 

 west of Geissen, whilst the wind was blowing 

 in the direction of the town. When several 

 hundred pounds of it were distilled in a copper 

 still, and the first two or three pounds evapo- 

 rated with the addition of a little muriatic acid, 

 a very distinct crystallization of sal-ammoniac 

 was obtained ; the crystals had always a brown 

 or yellow colour. 



" Ammonia may likewise be always detected 

 in snow-water. Crystals of sal-ammoniac were 

 obtained by evaporating in a vessel with muri- 

 atic acid several pounds of snow, which \vere 

 gathered from the surface of the ground in 

 March, when the snow had a depth of ten 

 inches. Ammonia was set free from these 

 crystals by the addition of hydrate of lime. 

 The inferior layers of snow, which rested upon 

 the ground, contained a quantity decidedly 

 greater than those which formed the surface. 



" It is worthy of observation, that the ammo- 

 nia contained in rain and snow-water pos- 

 sessed an offensive smell of perspiration and 

 animal excrements, a fact which leaves no 

 doubt icspecting its origin. 



"Any one may satisfy himself of the presence 

 of ammonia in rain, by simply adding a little 

 sulphuric or muriatic acid to a quantity of rain 

 water, and evaporating this nearly to dryness 

 in a clean porcelain basin. The ammonia 

 remains in the residue, in combination wrn 

 the acid employed; and maybe detected either 

 by the addition of a little chloride of plat'nmc , 

 or more simply by a little powdered lime, 



