MENURA. 



MEBCURT. 



774 



lanceolate, rounded at the base, deep-green, smooth, or hairy on the 

 under side; the upper floral leaves small, lanceolate, subulate, shorter 

 than the flowers ; whorls few, lax, the uppermost collected into a short 

 oblong obtuse reddish spike, the lowermost remote, with the cymes 

 shortly stalked ; bracts subulate, the outer ones as long as the calyx : 

 pedicels quite smooth; teeth of the calyx hispid, subulate, erect. 

 Peppermint is an aromatic stimulant, and the most pleasant of all the 

 mints. It is employed in medicine for several purposes ; the volatile 

 oil is an antispasmodic. 



M. Pultgium, Pennyroyal, also a British plant, is found in wet 

 ditches in most parts of Europe, also the Caucasus, Chili, and Teneriffe. 

 The stems are procumbent or prostrate, very much branched, more 

 or less hairy, rooting ; leaves scarcely half an inch long, often much 

 less, stalked, ovate, obtuse, with a few shallow unequal serratures full 

 of pellucid dots, and a little hairy, chiefly underneath ; whorls sessile, 

 numerous, many-flowered, globose, distant, large in proportion to the 

 foliage ; flowers light-purple, or nearly white ; calyx hispid, 2-lipped, 

 villous in the inside of the throat. The properties of this plant are the 

 same as the other mints. It is supposed to possess peculiar power as 

 an emmenagogue and antispasmodic. 



The other British species of the genus are : 



If. rotnndifolia, Round-Le,aved Mint, having sessile leaves, crenate, 

 serrate, wrinkled, shaggy beneath, and lanceolate bracts. 



M. sylvestris, Horse-Mint, has subsessile leaves, serrate, hoary 

 beneath, and subulate bracts. 



M. o'/natica, Capitate-Mint, is distinguished by its stalked leaves, 

 the uppermost being shorter than the whorls ; whorls few, subglobose, 

 capitate, the uppermost terminal. 



M. pratensis has nearly sessile leaves, the floral leaves acute, serrate, 

 the smaller ones longer than the whorls ; whorls distant, subglobose ; 

 calyx bell-shaped ; teeth hairy. It is a rare plant. 



M. tativa, Whorled Hairy Mint, has stalked ovate leaves, the upper 

 ones similar but smaller, all longer than the whorls ; calyx tubular or 

 bell-shaped, with triangular lanceolate teeth. 



M. anentit, Corn-Mint, is known by its stalked ovate or elliptical 

 serrate leaves, the upper leaves similar and equally large ; calyx 

 bell-shaped ; teeth triangular, an broad as long. 



(Babington, Manual of British Botany ; Lindley, Flora, Medico,.) 



MENURA. [MANUKA.] 



MENYANTHES, a genus of Plants belonging to the natural order 

 (irntianaceo!. It has a 5-parted calyx ; corolla funnel-shaped, with an 

 induplicate aestivation ; the limb spreading, 5-lobed, equal, stupose ; 

 stigma capitate, furrowed; capsule 1-celled, 2-valved, with the placentae 

 in the middle of the valves. 



M. trifoliata, Buckbean. is common in spongy boggy soils in Europe, 

 North America, and Great Britain. The rhizoma penetrates horizon- 

 tally in the bog-earth to a great distance, regularly intersected with 

 joints at the distance of about half an inch from each other ; these 

 joints are formed by the breaking off of the old petioles and their 

 hcaths; the leaves proceed from the end of the rhizoma on long 

 stalks furnished with broad sheathing stipules at the base ; they are 

 trifoliate, nearly oval, glabrous, somewhat fleshy, and slightly repand, 

 or furnished with many irregularities at the edge, which hardly pre- 

 vent them from being entire ; scape round, ascending, smooth, bearing 

 a conical raceme of flowers ; peduncles straight, supported by ovate 

 concave bracts ; calyx erect, somewhat campanulate, 5-parted, per- 

 sistent; corolla white, it! tube short; border 5-cleft, spreading, and 

 at length revolute, clothed on the upper part with a coating of dense 

 fleshy obtuse hairs ; stamens 5, shorter than the corolla, and alternate 

 with its segments ; anthers oblong, arrow-shaped ; ovary ovate ; stigma 

 bifid, compressed ; capsule ovate, 2-valved, 1-celled ; seeds numerous, 

 minute. All the plant, the root especially, is intensely bitter. It is 

 considered to be a valuable tonic. Large doses produce vomiting, 

 and frequently powerful diaphoresis. It is recommended in intermit- 

 tent and remittent fevers, gout, hepatic complaints, rheumatism, 

 dropsy, scurry, and worms. 



(Lindley, Flora Medico,.) 



MEPHITIS. [MUSTELID*.] 



MERCENA'RIA, Schumacher's name for the Venus mercenaria of 

 authors, which passes current as money, under the name of Wampum, 

 among the Indians of North America. [VENERID.S.] 



MERCURIA'LIS, a genus of Plants belonging to the natural order 

 Euphorb'uKCa. It has dioecious or moucccious flowers ; the perianth 

 2-3-parted ; with 9 to 12 stamens in the male flowers; the style short 

 and forked in the female flowers ; the capsule 2-celled ; the cells 

 1 -seeded, bursting at the back. The species are herbs ; two of them 

 are natives of Great Britain. 



M, perennit, Perennial Mercury, has a simple stem ; the leaves 

 stalked, ovate-oblong, rough ; the female flowers on long common 

 stalks ; the root creeping. It is a native of woods and thickets. It 

 i* considered to be very poisonous, though some old writers speak of 

 it as being boiled as a pot-herb. According to Sloane, it produces 

 violent vomiting, diarrhoea, stupor, convulsions, and even death. 



M. annua, Annual Mercury, has the stem branched, leaves stalked, 

 ovate or ovate-oblong, smooth ; the female flowers nearly sessile ; the 

 root fibrous. It is a common plant in waste cultivated lands. It 

 once had a place in the British Parmacopceia on account of its sup- 

 posed efficacy as an emmenagogue, but it is not now used for that 



purpose. The leaves abound iu mucilaginous matter, and are cooked 

 and eaten in Germany in the same way as we eat spinach. Professor 

 Burnett has pointed out the peculiar instability of the stamens of this 

 plant. At the period when they are fully developed if they are 

 touched they become loosened from their footstalks, and vault off 

 elastically towards the pistilline flowers. 



(Burnett, Outlines of Botany; Babington, Manual of British Botany) 



MERCURY, or QUICKSILVER. This metal, which possesses the 

 remarkable property of being fluid at usual temperatures, has been 

 known from the remotest ages. Although it is met with in very large 

 quantity, yet the mines occur in comparatively few places ; those of 

 Almaden in Spain, and Idria in Carniola, are the most important. 

 There are however mines of this metal in Hungary, Transylvania, and 

 the district of Deux Fonts in Germany. Mercury has been obtained 

 for a very long time in China and Japan, and although the amount of 

 the produce is unknown, there is every reason to think it considerable ; 

 it is also found at Huancavelica in Peru. 



Mercury is always obtained from cinnabar, which is a bisulphuret of 

 the metal. It is found at Almaden in a dark-coloured slate intermixed 

 with quartzite; sometimes, as in the district of Deux Fonts, the cinna- 

 bar occurs in the subordinate porphyries ; and at Idria it is found in 

 the subordinate bituminous schist, but rarely in limestone itself. 



The cinnabar which is found in coal-sandstone is often accompanied 

 with argillaceous and bituminous schist, and imprinted with fishes and 

 plants, often with combustible fossils, and sometimes even intimately 

 mixed with coal. 



Pliny states (xxxiii. 7) that Callias, an Athenian, discovered the 

 preparation of vermilion, or cinnabar, B.C. 505. He also mentions 

 the mines of Almaden [ALMADEN, in GEOG. Div.] as producing in his 

 time 10,000 Roman pounds annually ; but this was not the amount 

 which the mines could have produced, for the supply was purposely 

 limited. Le Play, a French geologist, who visited Almaden in 1833, 

 describes the mines as being richer than at any former period, 

 furnishing annually nearly 2,244,000 Ibs. of mercury. About 700 

 workmen are employed under ground, and 200 iu the operations con- 

 nected with the extraction of the metal from the ore at the surface. 

 The mines were visited by Capt. Widdrington in 1843. [ALMADEN.] 



Formerly mercury was imported in packages of 50 or 60 Ibs. weight; 

 the metal was poured into a fresh sheep-skin, from which the wool 

 was taken off, the ends were tied tight, and the sort of bag thus made 

 was inclosed in a second skin, and that in a third, and three or four 

 bags were packed in close barrels. Of late years however mercury 

 has been brought to this country in wrought-iron bottles. 



Various processes are adopted for the purpose of separating the 

 mercury from the ore, all of which depend upon the volatility of the 

 metal, its conversion into vapour iu distilling-vessels or retorts, and 

 its condensation by cold. In order to separate the sulphur from the 

 metal, either iron or lime may be employed ; the first forms sulphuret 

 of iron, and the latter of calcium, with the sulphur, and the metal is 

 thus set free, volatilised, and condensed. The retorts employed are 

 made of cast or sheet iron, or earthenware. 



According to Dumas the following mines yield annually the annexed 

 number of quintals of mercury (a quintal is 108 Ibs. avoirdupois 

 nearly) : 



Almaden 

 Idria . 

 Hungary 

 Transylvania 

 Deux Ponts . 

 Palatinate 



35,280 46,400 



We may perhaps reckon the average at about 2000 tons. 



The properties of mercury are that it is fluid, of a silvery white 

 colour, and possesses a high degree of lustre ; it is inodorous, tasteless, 

 unacted upon or very slightly by exposure to air at common tem- 

 peratures, and not at all by water at any temperature. The 

 specific gravity of mercury is about 13'568. It boils at 670 ; the 

 density of its vapour is 6*976 ; and yet, as shown by Priestley, it 

 vaporises at common temperatures, and Faraday has confirmed the 

 observation. At 40 below Zero, mercury becomes solid, crystallises 

 in octohedrons, and gives a dull sound like lead ; at the moment of 

 congelation it contracts considerably ; for while its density at 47 is 

 13'545, that of frozen mercury is 15'612; when in this state it is 

 malleable, and may be cut "with a knife. 



Mercury is a good conductor of electricity and of heat, but its 

 capacity for heat is extremely small; it expands uniformly at all 

 temperatures between its boiling and freezing points. When mercury 

 is pure it assumes the spherical form in small portions, but when it 

 contains other metals, it forms into long strife ; a very minute 

 admixture is sufficient to produce this effect ; when thus impure it 

 must be subjected to distillation, by which the mercury is volatilised, 

 and the metals mixed with it remain ; or it may be purified to a 

 considerable extent from the more oxidisable metals by agitation 

 with dilute nitric acid. The minerals in which mercury occurs are 

 not numerous. 



