4C H50, P2010 2C HO, C16H12O6 . 2CH.S, CO4 Xanthic ether (disulphocarbonic ether). Detailed information concerning the whole of the compounds of ethyl (except those discovered since the year 1856), will be found in Gerhardt's Traité de Chimie Organique.' ETHYL, used in chemical nomenclature as a prefix, is employed to denote the presence of ethyl in the compound to which the name is applied; thus ethyl-camphoric acid denotes camphoric acid containing ethyl. All such compounds will be found mentioned or described under ETHYL. ETHYLAMINE. [ORGANIC BASES.] ETHYLENE. (CH). Olefiant gas Elayl. Ethylene is one of the illuminating constituents of coal gas. It is also a common gaseous product of the destructive distillation of other organic substances besides coal; resins, fats, oils, caoutchouc, &c., all yield ethylene when heated in close vessels. When however this gas is required in a state of purity, it is always produced by heating together one part of alcohol and six or seven parts of concentrated sulphuric acid, and conducting it first through a Woulf's bottle containing milk of lime to remove any sulphurous acid, and then through a bottle containing strong sulphuric acid to absorb vapours of alcohol and ether. The reaction by which the olefiant gas is produced, simply consists in a dehydration of the alcohol by the acid, thus: but other decompositions occur simultaneously, for the mixture in the generating vessel gradually darkens in colour, and a black gelatinous mass is the final product. Ethylene is colourless, tasteless, and irrespirable, has a peculiar odour, is of sp. gr. 09784, and may be liquified by the combined aid, of great pressure and intense cold. It is almost insoluble in water, and but slightly soluble in strong sulphuric acid. Anhydrous sul, phuric acid absorbs it in large quantity. It is inflammable, burning with a highly luminous flame. Mixed with twice its volume of chlorine and the mixture ignited, rapid combustion ensues, hydrochloric acid gas is evolved, and a dense cloud of carbon at the same time produced. Ethylene has the property of combining directly with two equivalents of chlorine or of bromine, iodine, and sulphur, forming the compounds Moreover, as with ethylene itself, so with each of the bodies just enumerated, two equivalents of chlorine or of bromine can unite and form a second series of compounds. Such a compound is the chloride of perchlorethylene (C,C,, Cl), or sesquichloride of carbon (CC), while perchlorethylene itself is the protochloride of carbon (CC1). [CARBON, chlorides of.] Ethylene combines with anhydrous sulphuric acid, forming crystals of anhydrous ethionic acid (CH, 4SO). Cold water converts the latter into hydrated ethionic acid (CH, 4SO,, 2HO), which is by ebullition transformed into isethionic acid (C,H,, 2SO3, 2HO). Ethionic acid is bibasic, isethionic acid monobasic; they both combine with bases to form salts that are mostly crystalline. Dutch liquid. Ethylene was discovered by some Dutch chemists in 1795. It was called olefiant gas, because when brought into contact with chlorine over water the two combined to form a yellowish oily liquid that floated on the surface of the water. This oily chlorine compound has always retained the name of Dutch liquid, though its true composition (C.H.Cl2, chloride of ethylene, mentioned above) is well known. It was the source of that interesting series of ethylene derivatives already enumerated, and has thus greatly aided the advancement of the now well known chemical doctrine of substitution. ETRUSCAN ARCHITECTURE. We have no remains of Etruscan temples or other important buildings, but we know from ancient autho rities that the Etruscans constructed sumptuous public and private edifices; and we can form some idea of their style from their hypogei or sepulchral monuments, and also from some of their cinerary urus which have representations of temples (Micali, plate 72). Vitruvius, although he lived in an age when Etruscan art had undergone considerable alteration, characterises their buildings as baricephala, humiles, lata," low, wide, with heavy top ornaments. And this seems to be in keeping with the character of the people, grave, and more fond What is now called the of internal comfort than of external show. Tuscan order appears to have been a sort of rude Doric, which they probably adopted from the Greeks, though varying the type considerably. Vitruvius (iv. 7) gives a description of their temples, which appear to have been circular with a single cella, or rectangular with three cellæ; but they could have been neither large nor splendid: the ornaments, bronzes, and plastic figures seem to have been more elaborate than the structures themselves. The monuments which serve perhaps to throw most light on the subject of Etruscan architecture are the tombs, and especially those at Castel d'Asso, the Axia of Cicero ('Pro Cæcina,' 7), five miles southwest of Viterbo, where the face of a perpendicular cliff forming one side of the valley is sculptured all along for more than a mile with hundreds of fronts or façades of sepulchral monuments, the vaults themselves being excavated underneath. Similar sculptures on the rock are found at Norchia, about 15 miles south-west of Viterbo. (See Inghirami's plates.) But there are other of these tombs, which instead of presenting merely a façade cut out of the rock, are entirely detached, the rock being hewn away all round. Occasionally, where the rock is friable, the tomb is built instead of being hewn out of the solid rock. These monuments, which represent a primitive style of Etruscan building, strike by their resemblance to the Egyptian style in its ruder and simpler form. Plate 62 of Micali represents a monument between Monte Romano and Corneto with projecting architrave and lateral pillars. Another kind of tomb consists of a tumulus of earth, the base of which is surrounded by a podium or supporting wall of masonry. Tumuli of this kind remain in immense numbers about the sites of the ancient cities of Etruria. Some of these tumuli are of vast size. The largest, known as the Cocumella, at Vulci, is 240 feet in diameter, and 50 feet high; but is conjectured to have been originally about 120 feet high. This tumulus has near its centre two large towers, one square and the other round. In all these tombs the principal chamber resembles an abode of the living; and when opened has been found to contain biers or bedsteads, vases, and vessels of various forms, shields, weapons, and other articles, often of exquisite workmanship it is from these chambers that the Etruscan vases found in such profusion in every museum in Europe, have been obtained. The walls of the chambers in the tombs are sometimes panelled, and generally painted with mythic or festive scenes; and around them are seats, with arm-chairs and foot-stools hewn out of the solid rock. The vaulted roofs of these tombs show that the Etruscans were acquainted with the arch from a very early period. They employed the arch also in their gateways, bridges and aqueducts; and in constructing the Cloaca Maxima and other Roman cloaca. : In the time of Vitruvius the houses of the wealthy Etruscans had external porticoes or vestibula, in which the crowd of servants and clients remained in waiting. The Atrium is supposed by some to be of Etruscan invention. [ATRIUM.] But of these, as of their civic buildings, we have no vestiges remaining. Of their theatres there are no remains left. Their amphitheatres have also perished, with the exception of one at Sutri; but as this is hewn out of the rock, it can hardly be regarded as a type of constructed buildings of this class. It is 295 feet by 265, and, except in being more circular, differs little from the Roman amphitheatres-which were no doubt formed on the model of those of Etruria. [AMPHITHEATRE.] The great constructive skill of the Etruscans was especially shown in their massive walls and fortifications, and in their bridges, sewers, and other works belonging to what we now term civil engineering, rather than to architecture. The walls found in the northern part of Etruria are much more rude and massive than those of the south, where the stones, though large irregular blocks, are rudely squared and laid in horizontal courses; in all parts however the stones are laid without cement. They are of the kind known as Pelasgic, but the term is scarcely specific enough, as it does not distinguish any particular class of these walls; or the walls of any particular locality from other walls of the same kind. Some authors however conceive the Etruscans to have been altogether a Pelasgian tribe, and with them the term means that such walls are of Pelasgic origin. For fuller and more complete information of what is known respecting Etruscan architecture, see Inghirami, Monumenti Etruschi (text and plates, series IV.); Micali, Antichi Populi Italiani, and Monumenti Inediti; Orioli, Dei Sepolcrali Edifizi dell' Etruria Media; Abeken, Mittel Italien; Müller, Etrusker; Lepsius, Tyrrhenische Pelasgier in Etrurien; Dennis, Cities and Cemeteries of Etruria; Fergusson, Handbook of Architecture.) ETYMOLOGICUM MAGNUM (тd μéya érvμoλoyikóv), an important vocabulary of the Greek language, of which the author is unknown. Some suppose it was written by a grammarian of the name of Magnus. The idea that it was compiled by Marcus Musurus, the first editor, or the Calliergi, is disproved by the fact that this dictionary is referred to by Eustathius. Sylburg considers it as old as the 10th century: much older it certainly was not; for Theognotus, a writer of the 9th century, is quoted in it. The derivations in this work, like most of those attempted by the Greeks themselves, are based upon no principle, and though in some instances accidentally right, they are generally full of the wildest absurdities, as one might expect from the author being confined to mere guess-work. It is valuable however for containing a great many traditions with regard to the meanings of old or uncommon words, and it often enables the scholar to correct the errors of the corrupt but inestimable lexicon of Hesychius. The edition of Sylburg (1594) is very useful, and has an admirable index: the edition of the Etymologicum Magnum, by Schäfer, Lips., 1816, is a reprint of Sylburg's edition. The edition by Sturz, Lips., 1818, 4to., intituled Etymologicum Græcæ Lingua Gudianum, &c., is founded on the Codex Gudianus, which is more complete than that on which the edition of Musurus and the others already enumerated are based. ETYMOLOGY. [LANGUAGE.] EUMENIDES (Evμevides, the kind goddesses), a name given to the Erinyes, or Furies, a set of goddesses whose business it was to avenge murder, perjury, injustice to parents, and the violation of the rites of hospitality. They were also called Semna, or " venerable goddesses," both names being significative of the awe with which the Greeks spoke of the dread goddesses. The name Erinys was derived from the old Arcadian word erinuein (épiýew), 'to be angry.' (Pausan. viii., 25, 6.) These goddesses appear in the play of schylus which bears their name, not only as the instruments of wrath and the pleaders for justice against the matricide, Orestes, but also as the promisers of victory, prosperity, and all sorts of blessings to the Athenian people. Their abode, according to the Homeric notion, was Erebus; and they only come upon earth when recalled thither by the devotion of the accursed to their vengeance. Eschylus describes them as having black bodies, snakes twining about their hair, and eyes which dropped blood. Later they were depicted as rather solemn than terrible in aspect; but they continued to have snakes braided in their hair, and to carry them in their hands. The Eumenides are often represented on vases and elsewhere, but never of the terrible Eschylus type. The site of the temple of the Eumenides at Athens, where their worship possessed a peculiar importance, was the north-east angle of the Areopagus, at its base. "There is a wide, long chasm there, formed by split rocks, through which we enter a gloomy recess. Here is a fountain of very dark water." (Wordsworth's Athens and Attica,' p. 79.) The Athenians sacrificed to the Eumenides, among other victims, black sheep : no wine was mixed up with the libations offered to them, but only oil, honey, and water, in three separate libations, out of different vases. (Soph., ' Ed. Col.,' 469, &c.) Of the number of these goddesses we have contradictory accounts; in the play of schylus it is pretty certain that there were fifteen in the chorus. By later writers their number is more limited, some making them to be only three in number; and their names Alecto, Megara, and Tisiphone. (Müller's ‘Eumenides,' § 10.) Every question connected with these divinities is accurately and satisfactorily discussed by Müller in the second essay at the end of his edition of the Eumenides,' §§ 77-93. See also Böttiger's 'Furienmaske,' and Millin's Orestéide.' EUNUCH (evvoûxos, eunuchus, literally, 'one who has the care of a bed'). The Greek word may be considered as descriptive of the functions of those who were made eunuchs, it being usual among the Persians to entrust the care of their wives and daughters to such persons. It does not appear that eunuchs were made by the Greeks; this peculiar species of barbarity was a Persian practice (Herod. vi. 32); though the Greeks sometimes carried on the trade of making eunuchs, whom they sold at Ephesus and Sardis to the Persians for high prices, the Persians considering that eunuchs generally were more trustworthy than other men. (Herod. viii. 105.) Tavernier tells us that in the kingdom of Bootan 20,000 eunuchs were annually made in his time to sell to other nations; and the seraglios of the East are principally served and guarded by them to the present day. The Christian emperors of Rome forbade the practice of making eunuchs, particularly Constantine; and Justinian imposed a law of retaliation upon such as exercised this inhumanity. In Italy, however, EUCALYNE (C,H,2012). A saccharine substance recently obtained the process of castration was much more recently practised upon by M. Berthelot in the fermentation of melitose : Eucalyne is a syrupy unfermentescible sugar, isomeric with melitose. EUCHARIST (euxapioría, thanksgiving) is a Greek name of the Christian sacramental act otherwise called the Communion, or the Lord's Supper; and, in contradistinction from these appellations, it particularly expresses the idea of thankfully commemorating the mediatorial sacrifice of Christ; or, according to others, the name was assigned in reference to the fact that, when Jesus enjoined the observance of the rite, he gave thanks. [COMMUNION.] EUCHLORINE. [CHLORINE, oxygen and chlorine.] EUCHRÖIC ACID (C,H,N,O16? or C,H,NO). A colourless, crystalline acid, the ammonia salt of which is formed as a bye-product in the preparation of paramide. It is distinguished by the production of a beautiful blue colour by contact with metallic zinc. The blue colouring matter thus formed has been termed euchrone, but it has not been analysed, on account of the extreme facility with which it decomposes. EUCHRONE. [EUCHROIC ACID.] children intended to supply the operas and theatres of Europe as singers. The Council of Nice condemned those who from excess of zeal made eunuchs of themselves. Persons so mutilated were not admitted into holy orders. The reader who would know more on this subject may consult the Traité des Eunuques,' 12mo, 1707, by M. d'Ancillon. Certain heretics of the 3rd century bore the name of Eunuchs who had the folly or madness, after the example of Origen, not only to castrate those of their own persuasion, but all whom they could lay hands on. They were also called Valesians, from Valesius, an Arab, who was their chief. (See Epiphanius and Baronius's 'Annals,' under the years 249 and 260.) EUPATORINE. An alkaloid of unknown composition, contained in the Eupatorium cannabinum. EUPHORBIC ACID. A crystalline acid of unknown composition, said to be contained in the Euphorbia cyparissias. Its existence is doubtful. EUPHORBIUM, improperly called a gum, or gum-resin, since it is entirely destitute of any gum in its composition, is the concrete juice of several species of euphorbia, either exuding naturally or from incisions made in the bark, therefore properly a cereo-resin. Much of the article found in British commerce is obtained from the Euphorbia EUDIOMETER. An instrument employed for the analysis and Canariensis, while that which occurs on the Continent is obtained from investigation of gaseous bodies. [GASOMETRIC ANALYSIS.] EUGENIC ACID. [CARYOPHILLIC ACID.] EUGENIN (CH2O?), a substance which deposits spontaneously from the distilled water of cloves; it crystallises in small lamina, which are colourless, transparent, and pearly, and in time they become yellow. The taste of eugenin is but slight, and the smell much less strong than that of the clove. It is soluble in alcohol and ether in all proportions. By the action of nitric acid, like the oil of cloves, it becomes immediately, even when cold, of a blood-red colour. It appears to be isomeric with CARYOPHYLLIC ACID. EULYTE. A nitrated product derived along with dyslite, from the action of nitric acid upon citraconic acid. Euphorbia officinarum (Linn.) and E. antiquorum (Linn.), and other African species, particularly from an undescribed species, called by the Arabs dergmuse. The branches of this plant are used in tanning, and to it, according to Mr. Jackson (Edinburgh Medical and Surgical Journal,' vi. p. 457), the morocco-leather owes its peculiarities. By the most recent chemical analyses, euphorbium seems to consist of resin, wax, and saline matter (mostly malates). The resin is the active principle, and differs in some respects from most other resins, particularly in its less solubility in alkalies. Euphorbium is a powerfully acrid substance, causing irritation and inflammation of the parts with which it comes in contact, and by sympathy affecting the nervous system. The dust received into the (See nostrils or eyes occasions violent sneezing and lachrymation, or even the Gospels' (vol. i., p. 126, &c.), gives a variety of learned and critical more serious affections of the eyes, so that it is necessary for those remarks on the word evayyexífew, as the translation of the Hebrew who grind this drug to protect the face by masks. Delirium and, bashar, læta annunciare,' to announce good tidings.' stupor approaching to apoplexy have followed the inhalations of the the word in Rose's ed. of Parkhurst's Gk. Lex. of the N. T.') dust. When swallowed, it causes, in small doses, vomiting and purgEVAPORATION is the transformation of liquid, and in some ing; in larger doses it produces inflammation of the stomach, and cases of solid substances into a gaseous state by the action of heat. sometimes proves fatal. It is now little used, even as an external According to circumstances the effect may take place slowly and application to produce vesication or ulceration, except by veterinary without any apparent movement of the surface of the liquid from surgeons, and even by them cautiously. It is sometimes used as an which the vapour rises, or it may take place rapidly, and be accomerrhine, largely diluted with starch, and enters into the composition panied by an ebullition. In the latter case, however, the process is of some cephalic and eye-snuffs; but it is apt to be violent in its termed vaporisation. [BOILING OF FLUIDS; EBULLITION]. In the proeffects. In case of poisoning by it, demulcent or oily fluids should cess of evaporation, electricity has some share, as will be noticed further on. be given, and venesection employed if much inflammation ensue. EU'PION, a liquid obtained by Reschenbach from vegetable tar, especially that from beech-wood. The process for procuring it is operose and complicated. Its properties are--that it is very limpid, colourless, inodorous, and tasteless; it boils at about 117° Fahr., and distils unchanged; it remains fluid at 4°. It is insoluble in water, but dissolves in alcohol, oil of almonds and of olives, oil of turpentine, naphtha, &c.; it dissolves chlorine and bromine, which are evolved when it is heated, and it also takes up camphor, stearin, and naph-earth is going on at all times, and over the surface of an ocean the thalin, at common temperatures, but when heated, in larger quantity; with iodine it forms a blue solution. It dissolves phosphorus, sulphur, and selenium when heated, but the greater portion is deposited on cooling. Caoutchouc swells in it, and when heated dissolves. It is not altered either by exposure to air or by acids or alkalies. It probably consists chiefly of hydride of amyl, or a mixture of the hydrides of the ethylic series of radicals. 17 EUXANTHIC ACID (C,,H,,O,,,HO). Purreic Acid. There is a yellow or brownish matter met with in commerce under the name of purrée, or Indian yellow. It is imported into Europe from the East Indies, but its origin is involved in obscurity; by some it is supposed to be a deposit which forms in the urine of the camel, the elephant, or the buffalo; by others it is believed to be an intestinal concretion of some animal. This material, whatever its origin, consists principally of the magnesia salt of a peculiar acid, to which the above name has been given. This acid is extracted by washing the Indian yellow with boiling water, and then dissolving it in boiling dilute hydrochloric acid. On cooling, this solution deposits pale yellow crystals of euxanthic acid. Euxanthic acid is very slightly soluble in boiling water, but very soluble in boiling alcohol. Cautiously heated in a narrow tube, euxanthic acid decomposes and forms a yellow sublimate, consisting of eucanthone, or purrenone :— C42H19022 = C4012012 + 2CO2+ 6Hо 18 EUXANTHONE. [EUXANTHIC ACID.] EVANGELIST is the Greek appellation Euangelistes (evayyeλoths, from eù and ayyeλos), which signified a messenger of any good news, as in Isaiah xli. 27, of the Septuagint version. In the first ages of Christianity it was a general name of all those who, either by preaching or writing, announced the "glad tidings" of the Christian revelation. The learned Hooker, in his 'Ecclesiastical Polity,' b. v. § 78, says that "Evangelists were presbyters whom the Apostles sent forth and used as agents in ecclesiastical affairs." They were similar to the class of ministers who in modern times are known as itinerant preachers. The deacon (subordinate minister) Philip is called an evangelist (Acts xxi. 8; see Grotius on the passage); so Ananias, Apollos, Timothy, and several others. St. Paul, in his epistle to the Ephesians (iv. 11), places evangelists in the third rank of ecclesiastical officers; thus, apostles, prophets, evangelists, pastors, teachers. Mosheim says the name was applied to all those, in the infancy of the Church, who had received the gift of tongues. The use of the term is now confined to the four writers to whom the canonical gospels are attributed,-Matthew, Mark, Luke, and John,-and the gospels themselves are not unfrequently, though incorrectly, called the Evangelists. St. Jerome states that the symbols of the four evangelists are a man, a lion, a calf, and an ox; but St. Augustine declares them to be a lion, a man, an ox, and an eagle. (Ezekiel, i. 5-10; Rev. iv. 7.) Dr. Campbell, in his 'Dissertation on If a liquid be placed in an open vessel, it will be found gradually to diminish in quantity by a sensible or insensible evaporation, and it will at length disappear: the quantity of vapour proceeding from the same liquid in a given time is evidently proportional to the area of the exposed surface; but, with equal temperatures, the escape of vapour from different liquids will be found to take place with different degrees of rapidity. An evaporation of the waters at the surface of the aqueous vapour held in the atmosphere amounts to an enormous quantity: much of this vapour is precipitated to the earth in the form of dew, rain, &c., but it is probable that the atmosphere, at any place, is never entirely free from it. The whole quantity of vapour which rises from a liquid having a given surface appears to depend upon the temperature of the liquid; but, in a given time and in the open air, it is influenced by the state of the atmosphere with respect to dryness or moisture: in dry weather, even in winter time, the evaporation is more considerable than in damp weather, but it is greatest when the atmosphere is both dry and warm. At equal temperatures, in a close vessel, the evaporation is the same whether the vessel containing the liquid contain also air or have the air exhausted from it; but in the latter case the quantity of vapour which a given degree of heat is capable of raising occupies the upper part of the vessel immediately, whereas in the former a certain time elapses before that quantity is disengaged. in the open air, in a given time, the atmosphere being calm, Dr. In order to obtain a knowledge of the quantity of water evaporated Dalton suspended some in a cylindrical vessel of tin from one end of the beam of a balance, and raised it successively to different degrees of temperature by heat: he weighed the water before and after each experiment, during the continuance of which the temperature was constant; and the difference divided by the number of minutes gave, for that temperature, the weight of the water evaporated in one minute from the exposed surface. At the boiling-point (212° Fahr.) the evaporation of water from one square inch of surface was found to be equal to 4 244 grains per minute, and at a temperature expressed by 138° one grain per minute: between these limits the quantities of the evaporation, per square inch, in grains, are nearly proportional to the heights, in inches, of the columns of mercury, whose weights are equivalent to the elastic forces of the vapour at the different temperatures. In these experiments no allowance was made for the effects depending on vapour previously existing in the atmosphere, these effects being very small compared with the elastic force of the vapour rising from the water at such temperatures. But Dr. Dalton, taking f to represent the elastic force of vapour in the atmosphere when at the point of saturation, and f to be the elastic force of the vapour in the actual state of the atmosphere, the temperature of the air in both cases being that which is indicated by the thermometer at the time of the experiment, found that the quantity of evaporation from a square inch of surface, at such temperature, was proportional to f-f', and might be expressed by 24 (f-f'). (Manchester Memoirs,' vol. 5.) The evaporation from ice has been determined by experiment both by Dalton and Gay-Lussac, and was found to be equal in quantity to that which, by computation, would take place from water at the same temperature. 4*244 To Dr. Dalton we owe also the discovery, admitting however that the aqueous vapour in the atmosphere has no influence on evaporation, that the quantity of vapour raised from a given surface of any liquid, at a given temperature, is directly proportional to the elastic force of the vapour at that temperature; therefore, if the elastic forces of the vapours from different liquids were correctly ascertained, a near approximation, at least, might be made to the amount of evaporation from those liquids. At a temperature equal to 212° (Fahr.) the elastic force of the vapour from water is equivalent to the weight of a column of mercury 30 inches high; the elastic force of the vapour of one kind of alcohol, to the weight of a column 68 inches high; and that of the vapour of one kind of ether, to the weight of a column 219 inches high. It is stated by Mr. Faraday that, at temperatures above 60° or 80° Fahr., there is a small evaporation from mercury; at lower temperatures he could detect none; and he concludes that, below the temperatures just mentioned, the gravity of the particles of mercurial vapour exceeds their elastic force. In this material, as well as in all liquids which boil at high temperatures, the elastic force of the vapour is very small. Sulphuric acid, for example, boils at 640° Fahr., but it emits no vapour at ordinary temperatures. Most solid substances have vapours of such low elasticities, that the highest natural temperature cannot convert them into vapour: and hence Mr. Faraday concludes that the atmosphere does not contain any vapours of earthy or metallic substances. Camphor evaporates readily at ordinary temperatures, and deposits crystals on that side of the glass vessel which contains it which is nearest to the light. When ice is introduced into the Torricellian vacuum it immediately depresses the mercurial column upwards ofths of an inch. This is at 32°, but even at zero the tension of the vapour of ice amounts to ths inch: it is in consequence of this evaporation that drifts of snow and patches of ice disappear even during the continuance of severe frost. A few cases occur in which a body passing from a liquid to a solid form acquires thereby an increase of temperature, and the most remarkable case is afforded in the freezing of water. While still existing in a liquid state, water has had its temperature reduced so low, that a Fahrenheit's thermometer in it indicated no more than 5°; but on being made to crystallise, by agitation or otherwise, so much caloric was immediately evolved, that the thermometer rose to 32°. But when, by evaporation, a liquid is transformed into a vapour, heat is abstracted, and a thermometer in the liquid indicates a depression of temperature, or the liquid becomes cooled. In some parts of India, ice is produced by exposing water during the night in flat unglazed earthen vessels resting upon any imperfectly conducting substances, as sugar-canes, dry stems of maize, and the like. The dryness of the air allows a considerable evaporation to take place, and a thin film of ice is produced. Similar processes are employed in other countries for the purpose of reducing the temperature of liquids. [COOLER.] To a similar cause must be referred the icy caverns of the Jura, of Connecticut, and of Illetzkaya in the steppes of the Kirghis; namely, the powerful evaporation of moisture caused by the vicinity of the warm and dry external air. Rain,' Oxford, 1859) suspended by means of silk threads, in a warm EVERITT'S SALT. [CYANOGEN, diluted hydrocyanic acid.] EVERNESIC ACID. Synonymous with EVERNINIC ACID. EVERNIC ACID (CHO), a crystalline acid, homologous with lecanoric acid, extracted from a species of lichen, the Evernia prunastri. [LICHENS, COLOURING MATTERS OF.] EVERNINIC ACID. [LICHENS, COLOURING MATTERS OF.] EVIDENCE (Judicial) denotes, in jurisprudence, the proper means of evincing the true state of facts which have become the object of judicial investigation; and the just use of such means for that end in these investigations is the proper object of those established rules which are received in the courts of justice as the law of evidence. This law originates in the practice of the tribunals, continues into the latest times for the most part still unwritten, and long retains the character of the age which conceived and formed it for immediate service. Gradually the course of ages, changing the manners and continually adding to the moral and intellectual wealth of the nation, brings with it the necessity at length of departing somewhat from the tradition of the fathers. Reforms are introduced by positive enactment, and other reforms succeed as confidence increases with experience of the improvement effected thereby in the administration of justice. In this way our statute-book comes to exhibit at distant intervals the traces of change, which might be studied with advantage, relative to the history and character of the nation, but from which little information could be derived respecting the principles and rules that constitute this branch of English jurisprudence. The great bulk of these remain at this day, as they have been for ages, the subject of tradition, the common law of the courts, the familiar rules of daily practice in the administration of justice. But we are apt to forget this when we turn to Justinian's Digest,' and point with something like contempt to one short chapter which appears there, as though it necessarily comprised all that was an error of the same kind with his who should assume that in the fragmentary provisions of our statute-book he finds the whole of the English law upon the same subject; but the wrong would be so much greater, as it is done to the memory of a people whose jurisprudence has been the light of modern nations and the cherished wealth of the greatest minds, and which for its wisdom and rectitude still secures them the position and authority of the masters of the world. The pressure of the atmosphere on the surface of a liquid may retard but does not prevent the evaporation from taking place. Vapours, like gases, mix with other aëriform fluids according to their own laws, and as if they were diffused through a vacuum. Each atmosphere of vapour in the compound atmosphere acts on its own particles alone; so that the aqueous vapour in the atmosphere acts by pressure only on itself. The time that is occupied before a given space is saturated with a vapour varies inversely with the pressure; and with different vapours, under the same pressures, the time varies with the diffusive-known to the Roman law on the subject of evidence. This is probably ness of the vapour. [DIFFUSION.] The conversion of a liquid into a vapour is facilitated by placing the vessel containing the liquid under the receiver of an air-pump and extracting the air: but the vapour itself acts by its elastic force on the surface of the liquid, and impedes, at least for a time, the escape of more than a certain quantity. Daniell found that when water was evaporated under the receiver of an air-pump in the presence of sulphuric acid, the rate of evaporation was inversely as the pressure. Consequently the cooling process may be greatly accelerated by employing some means of absorbing the vapour as fast as it is formed, thus allowing the evaporation to go on without impediment. The means of accomplishing this end were discovered by Sir John Leslie, who placed a shallow open vessel containing sulphuric acid or muriate of lime along with the vessel containing the water from which an evaporation was to take place under the receiver of the air-pump; when the vapour was absorbed as it rose, and the water was speedily converted into ice. [FREEZING APPARATUS; CRYOPHORUS.] If a glass bottle containing water be covered with a cloth which is kept constantly wet by the application of water, the evaporation from the wet cloth will soon diminish the temperature of the water which is in the bottle. A similar effect is produced, but in a higher degree, on moistening the bottle with some spirit, as alcohol; and if a cloth dipped in alcohol be applied to the ball of a thermometer, the mercury in the tube will descend while the evaporation continues: the cooling is found to be so much greater as the spirit is more volatile; and it appears to be the greatest when ether is employed. The degree of cold thus produced is increased by any means which will accelerate the evaporation: thus, by wrapping a piece of linen dipped in ether round the ball of a mercurial thermometer, and exposing the apparatus to a current of air, the mercury in the tube has been made to fall as much as 45°. Dr. Cullen (Essays, Physical and Literary'), of Edinburgh put a small quantity of water into a thin glass tube which was suspended in a vessel containing ether; and then, on placing the apparatus under the receiver of an air-pump and rapidly exhausting the air, the evaporation of the ether caused such a diminution of heat in the water that it was converted into ice. By a similar process, using sulphuret of carbon instead of ether, Dr. Marcet (Phil. Trans.,' 1813) succeeded in freezing mercury. Still more remarkable cases are given under EBULLITION. For the method of ascertaining the amount of moisture in the air under any given temperature, see HYGROMETER. The supposed connection between evaporation and electricity is noticed under ELECTRICITY, ATMOSPHERIC; and the importance of evaporation as a meteorological agent will be further considered under RAIN; METEOROLOGY, &c.; but we may here refer to the old opinion advocated by the Abbé Nollet and others, that "electricity increases the natural evaporation of fluids," and that it is more efficient in this respect when the vessels which contain them are conductors. Mr. Rowell ('Cause of Judicial evidence, considered with regard to its sources, is derivable from living witnesses, and from written instruments; and viewed with respect to its production in court, and admissibility as the means of judicial inquiry, it is subject to conditions which in the order of things demand our earliest attention. The first great condition of the admissibility of living testimony in this country is that it must be given under the sanction of an oath. It suffices, however, that it be such an oath as is binding on the conscience of the witness. No exclusive ceremony or form of words is prescribed by our law, and no further inquiry into the faith of the witness is permitted than is necessary to ascertain whether he acknowledges the existence and moral government of the Divine Being, and that he will punish falsehood and perjury, either in this life or that which is to come. Even that inquiry is not volunteered by the judge, though it is permitted to be made by the adverse party; for it is a presumption of law that every person, in this country, of sufficient mental capacity, entertains this faith, and the usual form of oath is tendered without preliminary question. But obvious incapacity of mind, whether it be the immaturity of young children or the defect of the insane, rebuts this presumption of the law, and imposes on the court the duty of making previous inquiry into the state of the witness's knowledge with regard to the nature of an oath. The exemption, at an early period, from this necessity, of certain religious sects who entertain conscientious objections to oaths of any description, has recently been extended to all persons who allege conscientious motives for their refusal or reluctance to take the oath. This is a modification, still in the spirit of the general rule, rather than any exception to it, made in favour of tender consciences which are hindered from following the common practice by a scrupulous and reverent obedience to what they regard as the Divine Will. Scarcely more an exception than this is the admission in evidence upon trials for homicide of the dying declaration of the injured person, who in that condition makes a statement unsworn of the circumstances under which he received his injury. These statements, says Lord Chief Baron Eyre," are declarations made in extremity when the party is at the point of death, and when every hope of this world is gone; when every motive to falsehood is silenced, and the mind is induced by the most powerful considerations to speak the truth; a situation so solemn and so awful is considered by the law as creating an obligation equal to that which is imposed by a positive oath in a court of justice." |