70 



MITRE. 



MOABITES. 



510 



that the quantity of vapour in the air diminishes nearly uniformly with 

 the temperature from the equator to the poles. But as the quantity 

 of vapour which the air will hold at any given temperature is limited, 

 whenever that quantity is near or at the point of saturation, a very 

 small reduction of temperature renders the air misty, and a further 

 reduction converts the vapour into rain. 



As every reduction of the temperature of the air has a tendency to 

 destroy the transparency of the vapour which it contains, the atmos- 

 phere in our variable climate is seldom very clear. Soon after sunrise 

 however, in fair weather, the vapour near the earth having been 

 precipitated by the night-cold in the form of dew, and the sloping 

 raya of the sun having little power to raise more vapour, the air is 

 almost perfectly transparent, and every object has a clearness and 

 sharpness of outline which it never has at any other time of 

 the day. 



When the mist is very thick, it is called a fog. The fogs which fre- 

 quently occur hi London in the winter arise from the large quantity 

 of vapour produced by a great city being condensed by cold : and as it 

 is not carried off by winds, it is mixed with the smoke, and forms a thick 

 mass in and about the town ; while at a short distance the air is often 

 quite clear, and the limits of the fog may be distinctly observed. The 

 comparative cold of the local atmosphere in the valley of the Thames 

 below London, and its extension up the river, are also concerned in the 

 production of London fogs. 



The preceding is a very general view of the nature of mist and its 

 production. On our rivers and seas, towards the end of summer, 

 throughout the autumn and the beginning of winter its frequency and 

 amount are remarkable, and are the cause of much delay and risk to 

 the navigator. The immediate and topical dependence of the forma- 

 tion of mist, however, on the ordinary terraqueous surface, is upon the 

 temperature of rivers and collections of water. This was made a 

 special subject of attention by Sir H. Davy, in his second journey on 

 the continent of Europe, hi 1818, and he published the results in the 

 ' Philosophical Transactions' for the following year, pp. 123-131. He thus 

 describes the process by which mist is formed : "As soon as the sun has 

 disappeared from any part of the globe, the surface begins to lose heat 

 by radiation, and in greater proportions as the sky is clearer ; but the 

 land and water are cooled by this operation in a very different manner : 

 the impression of cooling on the land is limited to the surface, and 

 very slowly transmitted to the interior ; whereas in water above 45 

 Fahr., as soon as the upper stratum is cooled, whether by radiation or 

 evaporation, it sinks in the mass of fluid, and its place is supplied by 

 warmer water from below, and till the temperature of the whole mass 

 is reduced nearly to 40 Fahr. the surface cannot be the coolest part. 

 It follows, therefore, that wherever water exists in considerable masses, 

 and has a temperature nearly equal to that of the land, or only a few 

 degrees below it, and above 45 Fahr. at sunset, its surface, during the 

 night, hi calm and clear weather, will be warmer than that of the con- 

 tiguous land ; and the air above the land will necessarily be colder than 

 that above the water ; and when they both contain their due propor- 

 tion of aqueous vapour, and the situation of the ground is such as to 

 permit the cold air from the land to mix with the wanner air above 

 the water, mist or fog will be the result ; which will be so much the 

 greater in quantity, as the land surrounding or inclosing the water is 

 higher, the water deeper, and the temperature of the water, which will 

 coincide with the quantity or strength of vapour in the air above it, 

 greater." 



He proceeds to detail some observations hi proof of the correctness 

 of this view, made on the Danube from Ratisbon to Vienna, and at the 

 junctions with it of the Inn and the Ilz ; on the Khine, the Kaab in 

 Hungary, in Carniola, on the coast of Istria, and in Italy, including the 

 Po and the Tiber, and the small lakes in the Campagna of Rome. 



After mists have been formed above rivers and lakes, their increase 

 seems not only to depend upon the constant operation of the cause 

 which originally produced them ; but likewise, Davy inferred, upon 

 the radiation of heat from the superficial particles of water composing 

 the mist, which produces a descending current of cold air in the very 

 body of the mist, whilst the warm water continually sends up vapour ; 

 it is to these circumstances that the phenomena must be ascribed of 

 mists from a river or lake, sometimes arising considerably above the 

 surrounding bills. When rivers rise from great sources in the interior 

 of rocks or strata, as they have the mean temperature of the climate, 

 mists can rarely form upon them, except in winter, or late in autumn, 

 or early in spring. Great dryness in the air, or a current of dry air 

 passing across a river, will prevent the formation of mist, even 

 when the temperature of the water is much higher than that of the 

 atmosphere. 



This topical cause of the deposition of moisture from the atmosphere 

 is of considerable extent and variety in its modifications, and is not with- 

 out effect in the economy of nature, " for verdure and fertility, in hot 

 climates, generally follow the courses of rivers, and by the operation of 

 this cause, are extended to the hills, and even to the plains surround- 

 ing their banks." 



When the vapours in the upper regions of the atmosphere are con- 

 densed and become visible, they form clouds. [Ci.oun.] When those 

 near the surface of the earth arc condensed upon cold objects, they 

 form dew and hoar-froit. [DEW ; HOAB-FROST.] 



MITRE (from mitre, ulrpa, a head-band or diadem), the crown or 



jontifical ornament worn on the head by archbishops and bishops, and 

 n some instances by abbots, upon solemn oeeasions. 



The original meaning of Mitra, as it appears from Homer, is a 

 ' band " or " belt," worn by warriors to protect the lower part of the 

 sody. It is used by later writers to signify a band for the head, worn 

 ay the Greek females ; and also more particularly to indicate the head- 

 dress worn by Lydiaus, Phrygians, and other nations of Asia Minor, 

 which is sometimes called the Phrygian cap or bonnet. 



It is not known when it was first adopted by the hierarchy, but it 

 was probably not till the 7th century, when bishops were first esta- 

 blished by the Roman emperors. Gough, in his ' Sepulchral Monu- 

 nenta,' vol. i., p. cliii., says, " The mitres of Christian prelates were 

 oorrowed from the Apex or Tutulus of the Flamen Dialis." The pecu- 

 .iar form of the episcopal mitre, divided at the sides and pointed in 

 front, is believed to be a symbol of the parted or cloven tongues, " like 

 as of fire," which sat upon each of the apostles on the day of Pentecost. 

 The pope has four mitres, which are more or less rich according to the 

 solemnity of the feast-days upon which they are to be worn. The 

 cardinals anciently wore mitres, before the hat, which was first granted 

 to them by the council of Lyon in 1245. Furetiere, in his ' Dietion- 

 naire Universelle,' says that it was not till the llth or 12th century 

 that abbots were allowed to wear mitres. The Premonstratensians 

 procured a constitution, which was confirmed by Pope Innocent HI., 

 that all the abbots of that order should wear them. 



In England the mitre was certainly used by bishops as early as the 

 time of the Saxons, and continued as long as the Roman Catholic 

 religion was that of the state. Since that time (except at the coronation 

 of Elizabeth), the mitre has appeared only as an heraldic ensign, sur- 

 mounting the episcopal coat of arms, unless perhaps in some occasional 

 instance, such as Evelyn refers to in his 'Diary,' under 20th Dec. 1001. 

 " The bishop of Gloucester preached at the abbey at the funeral of the 

 bishop of Hereford, brother to the duke of Albemarle. It was a 

 decent solemnity. There was a silver mitre with episcopal robes borne 

 by the herald before the herse, which was followed by the duke his 

 brother, and all the bishops, with divers noblemen." Mitres were 

 however borne before the hearse at a bishop's funeral much later than 

 the occasion adduced by Evelyn. Anciently, the mitre, as an orna- 

 ment, seems to have descended from bishop to bishop. Among the 

 Cottonian manuscripts is an order, dated 1st July, 4th Hen. VI., for 

 delivering to Archbishop Chichely the mitre which had been worn by 

 his predecessor. That it was an ornament of great expense may be 

 gathered from the circumstance that Archbishop Pecheham's new 

 mitre, in 1288, cost 173/. 4s. Id. (See Ducarel's ' Excerpts from the 

 Lambeth Registers ; MS. Brit. Mus.') 



As an heraldic ornament the mitre of a bishop is only surrounded by 

 a fillet set with precious stones. The archbishop's mitre issues from a 

 ducal coronet, but this appears to be an innovation of comparatively 

 recent date. 



MITTIMUS, a legal term applied to certain writs and warrants 

 in which the word mittimus, " We (the King) send," is expressed or 

 implied. 



If a record of one court be, for any purpose, required to be trans- 

 mitted to another, as one court can exercise no direct authority over 

 another, the course is, for a writ to issue out of Chancery, requiring 

 the court in which the record is to certify the same to the Crown in 

 Chancery : and when the record is removed into the Court of Chancery 

 by this writ (of certiorari}, it is sent from the Chancery to the court 

 in which it is wanted by writ of mittimus. The term is, however, in 

 more frequent use as applied to the warrant by which magistrates 

 commit and send persons charged before them with offences to the 

 proper custody, in order that they may be forthcoming to answer the 

 charge, when ripe for judicial decision. 



MIXTURES, in Pharmacy, signify liquid medicines consisting of 

 several ingredients, either in a state of mechanical suspension in some 

 viscid medium, or in a state of complete solution. In preparing these, 

 care must be taken not to mix in the same prescription substances 

 which exercise an antagonising action on the body, or which are incom- 

 patible, from one ingredient decomposing another. Sometimes, how- 

 ever, it is the substance resulting from the decomposition of one or 

 more of the constituent articles which is desired, as in the compound 

 mixture of iron, and in this case decomposition of the materials is 

 indispensable. [ISCOMPATIBLES.] 



No greater quantity of a mixture should be prepared at one time 

 than is likely to be used before the compound is spoiled, either by the 

 atmosphere, if the materials are of a- vegetable kind, or by the action 

 of the various ingredients on each other. 



MNEMONICS. [MEMORY.] ' 



MNEMOSYNE. [MUSES.] 



MOABITES, a people descended from Moab, the son of Lot by his 

 elder daughter (Gen. xix. 37), and consequently related to the Ammo- 

 nites, with whom we find them closely connected in their subseouenl 

 history. [AMMONITES.] The earliest accounts represent them as dwell- 

 ing in the country on the east of the Dead Sea and the river Jordan, 

 on both banks of the river Arnon (Wady Modjeb),from which they had 

 driven out the Emim, who were said to be a tribe of giants. (Deut. ii. 

 11 ; Gen. xiv. 5.) The plains on the east of the Jordan near its mouth 

 were called from them the Plains of Moab. (Numb. xxii. 1 ; Josh, 

 xiii. 32 ; Deut. xxxiv. 1, 8.) At the division of Canaan among the 



