MEL 



[285] 



MEM 



grey, brown, or black rock, con- 

 sisting apparently, of a feldspathic 

 mineral intimately mixed with 

 augite, hornblende, magnetic iron, 

 &c. It is sometimes vesicular, 

 amygdaloidal, or porphyritic, and 

 and is said to be sometimes slaty. 

 Juices. 



MELA'STOMA. (from ^e\as, black, 

 and ffTopa, mouth, Gr.) A name 

 given to a genus of plants, belong- 

 ing to the order Melastomacea, 

 from the fruit staining the lips of 

 a black colour. 



MELEAGRI'NA. A genus of bivalve 

 molluscans, known as the pearl- 

 oyster. MeleagrinaB inhabit the 

 Persian Gulf, the coasts of Ceylon, 

 the sea of New Holland, the Gulf 

 of Mexico, and the coasts of Japan. 

 It attains perfection nowhere but 

 in the equatorial seas ; in the pearl 

 fishery of the island of Ceylon it is 

 the most celebrated and productive. 

 The pearls are situated in the 

 fleshy part of the oyster, near the 

 hinge. For one pearl that is found 

 perfectly round and detached be- 

 tween the membranes of the 

 mantle, hundreds of irregular ones 

 occur attached to the interior of the 

 shells, like so many warts: they 

 are sometimes so numerous, that 

 the animal cannot shut its shell, 

 and so perishes. 



ME'LILITE. (from [neXi, honey, and 

 X/009, a stone, Gr.) The name 

 given to a rare mineral, from its 

 honey colour. It occurs only in 

 very minute crystals, perfectly 

 regular and well defined, but not 

 larger than a grain of millet- seed. 

 These grains are of a cubic or 

 prismatic form ; their surface is 

 often coated with an oxide of iron. 

 They are glistening, semitrans- 

 parent, and will scratch glass. 



MELI'TA. (from met, honey, Lat.) 

 Honey-cake. A genus of echinites, 

 belonging to Catocysti. 



ME'LLATE. The name given to a 

 salt, in which mellitic acid is 



combined with any salifiable base. 



ME'LLITE. (from met, honey, and 

 X/0os, a stone.) Honey- stone. The 

 Honigstein of "Werner ; La Pierre 

 de miel of Brochant ; Pyramidales 

 Melichron-Hartz of Mohs. This 

 mineral was first observed in Thu- 

 ringia, where it occurs associated 

 with brown-coal. It is of a honey- 

 yellow colour, whence its name, 

 and is usually crystallized in small 

 octahedrons, whose angles are often 

 truncated. Fracture conchoidal. 

 Lustre shining or splendent. By 

 friction the crystals acquire a weak 

 negative electricity. They are 

 more or less translucent, or even 

 transparent, and exhibit double 

 refraction. Mellite may be distin- 

 guished from amber by its weak 

 electricity, and double refraction. 

 It consists of mellitic acid 41 -0, 

 alumina 14*10, water 44'8. 



MELOCRINI'TES. A genus of encrinites 

 established by Goldfuss. It is 

 found in the mountain limestone. 



MEMBBANA'CEOTJS. (memlranaceus, 

 Lat.) Resembling membrane. In 

 botany, a membranaceous leaf has 

 no distinguishable pulp between 

 the two surfaces. 



MEMBEA'NEOUS. (membraneus, Lat.) 

 Consisting of membrane. In this 

 and the preceding word may be 

 observed the difference between 

 words ending in aceous and eous : 

 those ending in aceous express a 

 resemblance to a material, those 

 ending in eous indicate the material 

 itself. 



ME'MBEANE. (membrana, Lat.) The 

 membranes of animals are thin 

 semitransparent bodies, which en- 

 velope certain parts of the body, to 

 which they furnish a covering for 

 their support and protection. Mem- 

 branes are modifications of cellular 

 texture, the surfaces of the plates 

 cohering so as to obliterate all the 

 cellular interstices, and being im- 

 pervious to fluids. Membranes 

 also line the interior of all the 



