ALVEARIUM. 



teeds of wheat only contain 0-6 of a grain, and 

 those of the barley and the oat only about 4 grains. 

 If some clay be dissolved in water, and some 

 aqua ammonia (hartshorn) be added to it, the 

 mixture will assume a milky whiteness, and if 

 left to stand awhile, a white substance will be 

 precipitated, called in chemical language alu- 

 mina. Prof. J. F. W. Johnston does not regard 



this as a nourishing element to plants. Its jse I [ re . S emblin^ spelt.] 

 in soils he considers entirely mechanical, bind- { u AMELIORATING 



AMERICAN BLIGHT. 



motion swifter than a walk. The amble may, 

 therefore, be considered as a defective pace, 

 not being common, and natural only to a very 

 few horses, which, in general, are weaker thaiu 

 others. Add to this, that .such amblers as 

 seem the strongest are spoiled sooner man 

 those which trot or gallop. 



AMEIX3ORN. A diseased sort of grain, 



ing the other materials together by its tenacity, 

 so as to furnish that degree of stiffness necessary 

 for the support of plants. Liebig takes a differ- 

 ent view of the subject. " It is known," he 

 says, " that the aluminous minerals are the 

 most widely diffused on the suface of the earth, 

 and, as we have already mentioned, all fer- 

 tile soils, or soils capable of culture, contain 

 alumina as an invariable constituent. There 

 must, therefore, be something in aluminous 

 earth which enables it to exercise an influ- 

 ence on the life of plants, and to assist in 

 their developement. The property on which 

 this depends is that of its invariably containing 

 potash and soda. 



" Alumina exercises only an indirect influ- 

 ence on vegetation, by its power of attracting 

 and retaining water and ammonia ; it is itself 

 very rarely found in the ashes of plants, but 

 silica is always present, having, in most places, 

 entered the plants by means of alkalies." (Lie- 

 big.)] (See EARTHS ; their use to vegetation.) 

 (Dan/, El. Chem. Phil. ; Thomson's System ; 

 Professor Schubler, Jour. Roy. Ag. Soc. vol. i. 

 p. 177; [Liebig's Organic Chem.]) 



ALVEARIUM. A term sometimes employed 

 to signify a bee-hive. 



AMAUROSIS. In farriery, is a total blind- 

 ness, without any altered appearance in the 

 eye. [This irremediable affection proceeds 

 from a paralysis of the nerve of sight, or 

 optic nerve.] 



AMBLE. In horsemanship, is a peculiar 

 kind of pace, in which both the horse's legs of 

 the same side move at the same t'me. In this 

 pace the horse's legs move nearer to the 

 ground than in the walk, and at the same time 

 are more extended : but what is most extraor- 

 dinary in it is, that the two legs of the same 

 side, for instance, the off hinJ and fore leg, 

 move at the same time ; and then the two near 

 legs, in making another step, move at once ; 

 the motion being performed in this alternate 

 manner, so that the sides of the animal are 

 alternately without support, or any equilibrium 

 between the one and the other, which must 

 necessarily prove very fatiguing to him, being 

 obliged to support himself in a forced oscilla- 

 tion, by the rapidity of a motion, in which his 

 feet are scarcely off the grojmd. For if in the 

 amhif he lifted his feet as in the trot, or even 

 in a walk, the oscillation would be such, that 

 he could not avoid falling on his side. 



Those who are skilled in horsemanship 

 observe, that horses which naturally amble, 

 and that they are considerably 



CROPS. In husbandry, 

 are such as are supposed to improve the lands 

 on which they are cultivated. Carrots, turnips, 

 artificial grasses, such as contain a large pro- 

 portion of nutritious materials, and y.ianv other 

 green vegetable products, especially if fed oi{* 

 [or ploughed in,] are considered as ameliorat- 

 ing; but all kinds of crops, carried off the hind, 

 are in some degree or other exhausters of the 

 ground; and green crops, such as have been 

 just mentioned, are only less so than crops of 

 grain or other ripe vegetables. The improve- 

 ment of lands, therefore, by what are commonly 

 termed ameliorating crops, depends, in a great 

 measure, upon the culture which the ground 

 receives while they are growing, and the 

 returns which they make to it in the way of 

 manure, after being consumed by animals. 



AMELIORATING SUBSTANCES. In agri- 

 culture, are such substances, as, when applied 

 to land, render it more fertile and productive. 



AMERICAN BLIGHT. [A popular, but 

 very inappropriate name used in England to 

 designate the injurious effects upon apple trees 

 caused by a species of plant-louse or Aphis, 

 (the Eriosnma mail, of Leach, and the Aphis 

 lanigera, of Illiger.) Its American origin is 

 rendered doubtful from the fact that nursery- 

 men in the Middle States have never witnessed 

 the mischievous effects described as common 

 in Europe from this kind of blight.] A de- 

 tailed account of the insect is given in the 

 Journal of a Naturalist, which, Math the correc- 

 tion of a few errors and oversights of the 

 author, we shall now follow. 



Early in summer, and even in spring, about 

 March, a slight hoariness is observed upon the 

 branches of certain species of our orchard 

 fruit. As the season advances this hoariness 

 increases, and becomes cottony ; and toward 

 the middle or the end of summer, the upper 

 sides of some of the branches are invested with 

 a thick, downy substance, so long as at times 

 to be sensibly agitated by the air. Upon exa- 

 mining this substance, we find that it conceals 

 a multitude of small, wingless creatures, which 

 are busily employed in preying upon the limb 

 of the tree beneath. This they are well enabled 

 to do, by means of a beak terminating in a fine 

 bristle ; this being insinuated through the bark, 

 and the sappy part of the wood, enables the 

 creature to extract, as with a syringe, the 

 sweet, vital liquor that circulates in the p. ant. 



This terminating bristle is not observable 

 in every individual, from being usually, when 

 not in use, so closely concealed under the 



the 



never trot, 



weaker than others. Colts often move in this breast of the animal, as to be invisible. In 

 manner, especially when they exert them- younger insects it is often manifested by pro- 

 selves, and are not strong enough to trot or truding, like a fine termination, to the vent 

 gallop. Most good horses, which have been (linns') ; but as their bodies become length- 

 over-worked, and on the decline, are also ob- ened, the bristle is not in this way observable, 

 served voluntarily tr. arnble, when forced to a , The pulp wood (alburnum) being thus wound- 

 78 



