ALVEARIUM. 



AMERICAN BLIGHT. 



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

 those of the barley and the oat only about 4 

 grains. It has been found in the largest pro- 

 portions in the entire plant of Turkey wheat, 

 100*parts of which yield 7-11 parts; and the 

 same proportion of the sun-flower yielded 3-72 

 parts, and the fumitory 14 parts. Small as 

 these proportions usually are, still there is no 

 reason to doubt but that these are absolutely 

 essential to the growth of the plant. It exists 

 in all cultivated soils in varying proportions, 

 and these are invariably smaller than those of 

 the other earths. 



[" It is known, that the aluminous minerals 

 are the most widely diffused on the surface of 

 the earth, and, as we have already mentioned, 

 all fertile soils, or soils capable of culture, 

 contain alumina as an invariable constituent. 

 There must, therefore, be something in alu- 

 minous earth which enables it to exercise an 

 influence 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- 

 &JT-)] (See EAKTHS ; their use to vegetation.) 

 (Davy, El. Chem. Phil. , Thomson's System , 

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

 p. 177; [Liebfg'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 time. 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 hind 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 ground. For if in the 

 amble 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, 

 never trot, and that they are considerably 

 u a leer than others. Colts often move in this 

 manner, especially when they exert them- 

 selves, and are not strong enough to trot or 

 gallop. Most good horses, which have been I 

 over-worked, and on the decline, are also ob- 

 served voluntarily to amble, when forced to a 

 78 



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 than 

 others. Add to this, that such amblers as 

 seem the strongest are spoiled sooner than 

 those which trot or gallop. 



AMEL-CORN. A diseased sort of grain, 

 [resembling spelt.] 



AMELIORATING 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 many other 

 green vegetable products, especially if fed off, 

 [or ploughed in,] are considered as ameliorat- 

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

 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 Eriosmna 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, with 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 plant. 



This terminating bristle is not observable 

 in every individual, from being usually, when 

 not in use, so closely concealed under the 

 breast of the animal, as to be invisible. In the 

 younger insects it is often manifested by pro- 

 truding, like a fine termination, to the vent 

 (anus) ; but as their bodies become length- 

 ened, the bristle is not in this way observable. 

 The pulp wood (alburnum) being" thus wound- 



