Aconitine

the active principle of Aconite, is most aetive poison. It is used medicinally in the of the Aconite Ointment for external apto painful surfaces. Internally, aconite administered mainly in the for in of the tincture, powerful drug, in the use of which much caution nece ary, Acorn, the corn or fruit of the oak (Angioac), formed of three coherent. carpels with perianth-tube, which terminates in a and becomes horny. Its three chambers and six ovules are aborted to one chamber with but one seed. The aeorp is surrounded the base by acup or cupule. The bitterne of seed varies both in species and in individuals, acorns of several kinds of evergreen oak being used as human food in the Med it err an can Swine, deer and goats, squirrels, pigeons, other aninuids feed largely upou acorns. Acorn shells. [ BALANID«A:.] Acorus, ® small genus of plants of the Aroid of which Acorus Calamus, the Bweet Sedge, commonly naturalised in Hurope. The starchy stem, or rhizome, of this plant con a fragrant oil, said to be tonic and stimulant, of use in ague and dyspepsia. It is used for as a candy, in aromatic vinegar, in gin and snuff, and for chewing to clear voice. 1t was formerly cultivated in Norfolk. is now imported from South Ru ia, Acosta, CHRIST OVAL, a Portuguese naturalist physician, who visited the East Indies, and Goa, in the 16th century, to seek for and plants, on which he wrote a treatise. diced in 1580 at Burgos, in Spain. Acosta, JoAQquim (d. 1852), a distinguished geoand historian in the military service first Columbia and afterwards of New Granada, In he began a series of explorations, which have 26 Acotyledons. ¢ 0) 4 ORT ENR Seeman added mach to our knowledge of South America. In 1848 he publiahed a valuable compendium on the discovery and colonisation of New Granada, and in 1849 he re-edited the works of Caldas, a learned antiquarian often quoter by Humboldt. Acotyledons, «® name somewhat inaptly applied to the cryptogamic portion of the vegetable Kingdom by analogy with the divisions Dicotyledon a and Monocotyledons, comprising all flowerle plants. It signifies that. their spores or reproductive elements do not. contain any cotyledon or embryonic leaf. Though this is strictly trac, as they do not at first contain even an embryo, in the higher Crypto game such as the Ferns an embryo is subsequently produced, one portion of which gives rise to a cotyledon, much as in Monocotyledons, Acouchy. [Acovrtt.] Acoustics, the science relating to those effects called sounds, their causes and transmi ion, qualities and analysiz, Drawing a bow acro 2 Violin-st ring causes itte vibrate. A certain effect is wodaced on the ear, an effect varying with dif erent. cars, or at different cistanees with the same ear, This effect is transmitted from the string to the tympanure er drarmoof the car by a vibratory motion of the particles of the air, or other clastic medium, which may intervenes Without an elastic inedium to transit this effeet no sound would be heard. Thus a bell ringinu inside the exhausted receiver of an air-pump cannot be herd, The velocity of transmi ion depends on the nature of the meduta, varying with its clast i city and with its density. If the elasticity be tnerenased the velocity will Inerease; if the density be inerease:| the velocity will devrease. ‘The rate at which sound travels in the curds LOO feet per second at OPC, in eres sing: about 2 fect per second for every degree Centigrade. The velocity of sound in hiquids is as acrale mach preater than in gases, and much greater in solids than in liquids, the elasticity increasing more rapidly than the density. Thus in water the velocity is 5,000 feet per second, and in iron L6,000 feet per second. ‘The chief laws of neoustics ate thus stated:--(a) The intensity or loudne of a sound varies inversely as the square of the distance of the sonorous body from the ear, Uf the distance is doubled the intensity is diminished to 4. (4) The intensity increases with the amplitude or extent of vibration of the sonoreus body; (Ce) it diminishes if the density of the wnedium is diminished, and (7) it is strengthened by the neighbourhood of other sonorous bodies. Henve the use of sounding-boxes in stringed instrnments, and of sounding-boards for the voice. Sounds vary in pitch or acutene if the frequency of the vibration varies; thus, if the number of vibrations per second be increased we obtain a higher note, if diminished we have a lower. If the number be doubled a note is heard that produces a certain physiological eect of samene . This note is the octave, or tirst harmonic. If trebled we got the second harmonic, and so on. The limits of hearing of the ordinary human car are from about second, different recognised tuning-fork nearly never frequencies pianoforte harmonics, monic notes timbre tingnish the INSTRUMENTS.] waves augment PLECTION, ing attached from of dise, structure with fish a little this teresting The cluding ovuin hydra-like known tions then this and away adult The serve group eved the asa square The same Irish founded Greeks situated the of by 1110. Leon gave Acre. 34 (Helmholtz) to 34,000 vibrations per but the range varies considerably with individuals. 261 vibrations per second are by our musical sense, as & used on a sounding-board gives us 2 pure note such as this, but as a rule we get simple notes corresponding to definite of vibration. Thus in sounding C on a it is eaxy to recognise some of the especially when the keys of the harnotes are kept down. This admixture of other tu the fundamental gives us the quality or of a sound, and we are thus enabled to dis between the voices of different people or sounds of different instroments. [MUSICAL Like other wave motions, sound may be reflected or refracted; they may each other or they may interfere. [RxE- REFRACTION, INTERFERENCE. ] Acraspeda, 4 sub-cla of HypRozoa, inc lud the umjority of the large permanently unjelly-tish. The main characteristic, which the name is derived, is the absence ct velum. The body consists of a bell-shaped in Which the polypite is) suspended; the may be compared to an open umbrella, a very short handle. In the craspedote jelly a velum or shelf runs round the umbrella, above the base, and limiting the opening; is absent in the Alerasyede. The most in feature In this group is its development. lite history is divided into three stages, ext he embryonic. After the free-swimming has become fixed. it develops into a small body, the Seyphistema (this stage is not in many forms) By a series of constrict his tube becomes transversely divided, and resembles a pile of saucers with ragged edges; is the Strubila stage. The constrictions deepen succe ive segments are ent off; these swim as Lphyre, each of which develops into the for in, which is sometimes of a gigantic size. four bodies on the margin of the disc, which as sensory organs, are covered by hoods. The is, therefore, often known as the “ covered- Medusie.” Aurelia, one of the commonest of larger jelly-fish round the British coasts, serves good type of the cla . AURELIA. ] Acre, a measure of land, consisting of 4,840 yards or 10 square chains, or 4 roods. measure of an acre in the United States is the as the English acre. but the old Scotch and acres were somewhat larger. Acre, ST. JEAN p’AcRE, or Accho, probably by Phoenicians, and known to the later as Ptolemais, is a fortified sea-port in Syria, on a projecting tongue of land that forms N.E. limit of the Bay of Acre, the promontory Mount Carmel being to the S.W. It was captured the first crusaders, 1104, and again by Baldwin, Salad in retook it, 1187, but Richard Coeur de and Philip August us won it back, 1191, and it to the Knights of St. John. In 1291 it again ee exception to the LIAMENT. | Act of Congre . Act of Parliament, Bill (q.v.) after both Hoscen of Royal A ent. Act of Settlement, by which all prior ing that of the were set «side tre of Hanover, this Act George on the death of for the settlement Act of Settlement, that Mr. Lecky aversion between which is the chief evils of Ireland.” Act of Toleration, relaxing the severe Di enters contained (q.v.), the Five-mile Act. Act of Uniformity to that statute quired to give their Prayer, and to services from it. clergymen resigned sine name pa ed persons who made book than Edward Acton, son and Auntonoé, mighty hunter, a woodland stream. trusion the podde and he was devoured Actewonidm, has existed since Actinia, one the sea anemones, of.théstructure Pi! "is one. ‘attached Ast. ( 24 insurer’s liability. [AcT oF Pan- [Concre .] the name given to a it has pa ed succe fully through Parliament and has obtained the It is then absolutely binding. an Act pa ed in 1700, claims to the throne, except i ue of William or of Anne, in favour of Prince Sophia, Elecand the heirs of her body; by I., her son, succeeded to the crown Anne. In 1652 Cromwell’s measure of Ireland, also known as the was pa ed; it is this settlement regards as “the foundation of the the proprietary and the tenants, cause of the political and social an Act pa ed in 1689 provisions against Protestant in the Act of Uniformity Act (q.v.), and the Conventicle (1662), the name given by which all ministers were rea ent to the Book of Common read the morning and evening In consequence of this Act 2,000 their livings. The Act of the in 1550 was directed against any use of any other form of prayer- V1.'s Revised Prayer-book. of Arista us, the child of Apollo, daughter of Cadmus. He was a and came upon Diana bathing in To punish him for his in- Sratuformen him into a stag, by his own hounds. «a family of GAsTEROPOD A which the Carboniferous period. of the commonest genera of which affords a good type ACTINIA, of that group. A. eqguina, “the of the commonest British species; to rocks, stones, and even crabs, ) all one height. it centre mouth leads this position upon method barbed ALCYONIUM, mesenteries eight includes been of some Minyas, some in usually range ment light from of actinic end end actinic gla , the Hence of the of of the in of the caused or tanical yet genus of in A, is its podia, greatly ring body Act i not roch a. eee mRNA pene ety round the coast. It consists of a fleshy cylinder to four inches in diameter and one inch in Its firm adherence to the object on which lives is secured by its flat base, the disc; in the of the upper end of the cylinder is the surrounded by rings of tentacles. The mouth to a short digestive tube, the stomodzum; is open below to the body cavity and is held in by radiating membranes, the mesenteries; these are the reproductive organs. Its only of defence is the shooting out of minute threads.