MUL 



MUR 



mineral with the colour and feel of tallow, { 

 found in a bog on the borders of Loch 

 Fyne in Scotland, and in one of the 

 Swedish lakes. It differs from every 

 known class of bodies. In volatility and 

 combustibility it resembles naphtha. 



MOYA. A term applied in South 

 America to mud poured out from vol- 

 canoes during eruptions. 



MUCIC ACID. An acid first obtained 

 from sugar of milk, and hence termed 

 saccholactic ; but as all the gums appear 

 to yield it, and the principal acid in the 

 sugar of milk is the oxalic, it is now 

 called mucic. 



MUCUS. One of the primary animal 

 fluids, perfectly distinct from gelatin. 



MUDSTONE. A local name for part 

 of the Upper Silurian Rocks of Mr. Mur- 

 chison. 



MUFFLE. A small earthen oven, 

 fixed in a furnace, and used in cupella- 

 tion, and other processes which require 

 the access of air. 



MUGI'LIDiE {mugil, the mullet). The 

 Mullet tribe ; a family of acaiithoptery- 

 gious fishes, including the genera mugil, 

 tetragonurus, and atherina. This family 

 is included in the cycloid order in the 

 system of Agassiz. 



MULLER'S GLASS. Another name 

 for hyalite, a siliceous substance found in 

 fissures in vesicular basalt and basaltic 

 greenstone. 



MULTILATERAL {multa latera ha- 

 bens). Having many sides; as applied 

 to a geometrical figure, bounded by more 

 than four straight lines. See Polygon. 



MULTILOCULAR {muUos loeulos ha- 

 bens). Having many loculi or chambers ; 

 a term applied to those shells which, like 

 the nautilus and ammonite, are divided 

 into many compartments. 



MULTINO'MIAL {multa nomina ha- 

 bens). Having many terms ; an alge- 

 braical expression denoting a quantity 

 which consists of an indefinite number of 

 terms, as« + b — c + x — y, &c. Such 

 a quantity is also termed a polynomial. 



MU'LTIPLE (multiplex, manifold). A 

 number which includes another a cer- 

 tain number of times ; thus 6 is a mul- 

 tiple of 3 or of 2 ; 18 is a multiple of 9 or 

 of 6. Hence, any number of equal mag- 

 nitudes added together give a multiple 

 of any one of them ; thus 6 + 6 + 6, or 

 18, is a multiple of 6. See Suhmultiple. 



Least common multiple. A common 



multiple of two or more numbers is one 



which contains each of them ; and, of 



course, the least such number is their 



227 



least common multiple. Thus 6, 12, 18, 

 &c. are all common multiples of 2 and 3 ; 

 but 6 is their least common multiple ; 12, 

 24, 36, 48, &c. are all common multiples 

 of 2, 3, 4, 6, and 12 ; but 12 is their lea.-t 

 common multiple. 



MULTIPLE POINTS. In Geometry, 

 when two or more branches of a curve 

 pass through the same point, this is 

 called a multiple point ; and it is equally 

 so called, whether the branches touch or 

 cut one another. 



MULTIPLICAND. That factor, num- 

 ber, or quantity in multiplication, which 

 is to be repeated the number of times 

 denoted by the other factor, or the mul- 

 tiplier. 



MULTIPLICATION. The arithme- 

 tical method of finding what number 

 would result from adding several of the 

 same numbers together. In other words, 

 it is the process of forming a multiple : 

 thus, to multiply 6 by 9, is to repeat 6 

 nine times, and to add all the results 

 together. This is the first and fundamen- 

 tal meaning of multiplication. The num- 

 bers multiplied are called factors, and 

 the result is called the product. 



MU'LTIPLIER. An instrument in- 

 vented simultaneously by Schweigger 

 and Poggendorf, for indicating the de- 

 flecting influence of an electric current, 

 and applied in cases in which the current 

 is so weak as to require its conduction 

 several times round the needle, thus re- 

 peating or multiplying the deflecting in- 

 fluence of the single current. 



MU'LTI VALVE (mulias valvas ha- 

 bens). Having many valves, as the 

 chitons among testaceous mollusca. 



MURiE'NIDiE {murcena, a lamprey). 

 Anguillidce. The eel tribe; the single 

 family of Malacopterygious or soft-spined 

 fishes, belonging to the section Apodes, 

 in which the ventral fins are wanting. 



MURAL CIRCLE. An instrument 

 for measuring the distances of stars from 

 the poles or the Zenith. It consists of a 

 circle constructed of metal, and mechani- 

 cally divided into equal parts, as degrees, 

 minutes, &c. A tube is adjusted to the 

 circle so as to revolve together with it on 

 an axis concentric with the circle. The 

 axis is let into a wall, and rendered ca- 

 pable of adjustment both in a vertical 

 and horizontal direction ; so that, like 

 the axis of the transit, it can be main- 

 tained in the exact direction of the east 

 and west points of the horizon, the plane 

 of the circle being consequently truly 

 meridional. 



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