Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/94

 MUM

produft is + s but when the figns of the fates arc unlike, the ftgn of the product is —.

Then if the quantities to be multiplied be fimple quantities, find the fign of the product by the laft rule ; after it place the product of the coefficients, and then fet down all the letters after one another, as in one word.

If the fa£tors be compound quantities, multiply every part of the multiplicand by all the parts of the multiplier, taken one after another, and then collect all the products into one fum ; which will be the product required. See Maclaurin, Saun- derfon^ or any other elementary writers. The reafon of the rule here given for the figns of the product, ■viz. That 4- by -J-, or — by — give 4-, and that + by — , or — by 4- give —, is apt to perplex beginners. But if it be confidered, that in all Multiplication the multiplicator is, ftricily fpeaking, a number, the difficulty foon vaniihes ; for, i°. When any pofitive quantity 4- a is multiplied by any po- sitive number + w, the meaning is, that 4- a is to be taken as many times as there are units in w, and therefore the product is evidently 4- na or na, the pofitive fign being omitted. 2\ When a is multiplied by w, then — a is taken as of- ten as there are units in #, and the product muft be — na. 3°. As Multiplication by a pofitive number implies a repeated addition, Multiplication by a negative implies repeated fub- traction; fo that when -\-a is to be multtpUd by ■ — «, the meaning is, that 4- a is to be fubtracted as often as there are units in n ; therefore the product muft be negative, being ' — na.

4 . When — a Is to be multiplied by — «, then — a is to be fubtracted as often as there are units in n ; but by the rules of fubtraction, to fubtract — a is equivalent to adding -j- a, and confequently the product is 4- na.

The id and ^tb cafes may be thus illuftrated, by the import and meaning of the figns 4- and —, -J- a — a muft be = o. Therefore if we multiply -\-a — a by «, the product muft vanish, or be nothing ; becaufe the factors — a = o. The firfi term of the product is -\-na by cafe I. therefore the fe- cond term of the product muft be ■ — n a> which deftroys 4- na ; fo that the whole product muft be 4- " a — na = fl - There- fore — a multiplied by 4- n gives — na. In like manner, if we multiply 4- a — a by — n, the firft term of the product being — k«, the latter term of the pro- duct muft 4- na y becaufe the two together muft deftroy each other, or their amount be <7, fince one of the factor a — a = o. Therefore — a multiplied by — n, muft give -\-iia. See Mdefauriti's Algebra, Parti, chap 4. Saunderfon's Algebra, Vol. 1.. p. 57. And Arrow's Euclid, Schol. Prop. 1. E- lem. 2.

MULTIPLIER, in arithmetic, the number multiplying. See the article Multiplicator, Cycl.

MULTIVALVES, in natural hiftory, the name of a general clafs of fhell-fifii diftinguifhed from the univalves, which con- lift of only one (hell, and the bivalves, which confift of two, by their confifting of three or more ihells. Of thefe there are much fewer fpecies than either of the uni- valve or bivalve clafs. A late accurate French author has ranked all the fpecies under fix genera, which are thefe: 1.

■ The echini or fea-eggs. 2. The vermiculi^ or fea-worms. 3. Balani or center-fhells. 4. The pollicipides or thumb- (hells. 5. The conches anatifera: or goofe-fhells. And 6. The pholades. Hift. Nat. Eclairc. part 2. p. 235. All thefe fee under ihcir feveral heads. •

MULTONES Juri, in our antient writers, an old coin of gold, having an Agnus Dei> flieep or lamb on the one fide, and from that impreflion called Multones, This coin was moll common in France, and fometim.es current in England. Pa- tent 33 Edw. 1. cited by the learned Spelman. Blount.

MULUD, in the materia medica, a word ufed by Avifenna and Serapio to exprefs a fort of litharge, called by the Greeks molyb- dites, as feeming to partake of the nature of lead alone, not of gold or filver, or any other metal, as they thought the argy- rites and chryfites did. This Mulud or molybdites was the leaft in efteem of all the kinds of litharge, and was of a dufky greyifh white colour. It feems to be the fame that Diofcorides means by peh'a and polia, and fometimes by lithargyrus Ski- lias, from the place whence it was brought,

MUMMY {Cycl.) — There are found at this time in Poland a kind of natural Mummies, or human bodies, preferved with- out the afiiftance of art. Thefe lie in coniiderable numbers in fome of thevaft caverns in that country. They are dried, with the flefti and fkiri flirunk up almoft clofe to the bones, and are of a blackifh colour. In the wars, which feveral ages ago laid wafte that country, it was common for parties of the weaker fide to retire into thefe caves, where their enemies, if they found it out, fuffocated them by burning ftraw, &c. at the mouth of the cavern, and then left the bodies ; which be- ing out of the way of injuries from common accidents, have lain there ever fince. Kzaczinjki Hilt. Pol.

Mummy, among the gardeners, is the term ufed for a fort of waxey compofition ufed in grafting. It is made of one pound of common black pitch, and a quarter of a pound of turpen- tine, put into an earthen pot with a cover fitted to it ; this is to be let in the open air, and the cover being taken off, the matter is to be fet on fire, and when it has burned a little

M U R

. while, it is to be quenched by putting on the cover. This is to be repeated till the mixture is of a proper confiftence, which is known by pouring a little of it on a pewter plate, on which, when it is enough, it will coagulate immediately. When it is of this confiftence, it is to he poured into another pot, and a little yellow wax is to be added to it, and then melting the whole together, it is to be kept for ufe. Miller's Gardener's Diet.

MUNDUS Patens, among the Romans, a folemnity performed in a little temple of a round form ; and dedicated to Dis, and the Infernal gods.

It was opened only three times in a year, viz. on the day af- ter the Vulcanalia, the ifh of October, and the yth of the ides of November, during which days the Romans believed that hell was open ; and therefore they never offered battle on thofe days, lifted no foldiers, never put to fea, nor married. Pitifc. in voc. See the article Vulcanalia.

MUNDUYGUACU, in botany, a name of the nux cathartica of the Weft Indies, a kind of great ricinus, or palma Chrifti. Pifi, 169.

MUNGATHIA, in zoology, the name given by fome to a fpecies of Indian ferret, of a reddilh grey colour, called alfo mungo.

MUNGO, in zoology, the name of an American animal of the ferret kind, called by authors viverra Indica ex grijeo-ru- fefcens, or the reddifh grey Indian ferret. Some call it alfo mungathia. Muf. Leyd. Cat.

MUNITION (Cycl.)— MvKniov-Shipi, in the navy, thofe which have ftores on board, to fupply the neceflaries to a fleet of men of war at fea.

In the time of an engagement, all the Munition-Raps and victuallers attending the fleet are to take their places and pro- per ftations in the rear of all the reft, and not engage in the fight, but attend fuch direflions as fhall be lent unto them, at all times, by the admiral.

MUNNY Shelter, in natural hiftory, a name given by the na- tives of the Eaft Indies to a fpecies of red orpiment, which they have plentifully there. It is of a glowing colour, and has a great many fhining fpangles in it. They give this in fevers, after it has been calcined : It firft melts in the fire, and then emits copious white fumes, fmelling like thofe of arfe- nic. Thefe are fupppfed to contain the poifonous parts of it, and it then becomes a fafe internal medicine, and is given with great fuccefs.

MUNTINGIA, in botany, the name of a genus of plants, the characters of which are thefe : The perianthium confifts of one leaf, divided into large pointed fegments. The flower con- fifts of five roundifh petals, of the length of the fegments ; of the cup. The (lamina are numerous capillary filaments, they are very fhort ; and the antherse are fimple. The germen of the piftil is globofe, and is covered with hairs ; there is noftyle, and the ftigma is capitated and pentangular in figure. The fruit is a globofe berry, with only one cell ; it is umbilicated by the ftigma. The feeds are very fmall and numerous, and are of a roundifh figure. Linnai Gen. Plant, p. 229. Pltt- micr, Gen. 6.

MUNYCHIA, Ma«>X'«, in antiquity, an anniverfary folemnity at Athens, upon the fixtecnth of the month munychion, in honour of Diana, fui named Munyckia. For the origin and ceremonies obferved in it, fee Potter, Archieol. Graec. 1. 2. c. 20. T. r. p. 414. feq.

MUNYCHION, Mwxiv, in chronology, the tenth month of the Athenian year. It contained twenty-nine days, and an- fwered to the latter part of our March and beginning of April. See tlie article Month. It had its name from the feftival nntnichia, kept in it.

MURifLNA, in the Artedian fyftem of ichthyology, the name of a genus of fifties, the charatt ers of which are thefe : They areof the malacopterigious or foft- finned kind. The branchioftege membrane on each fide contains ten {lender and curved bones ; but the fkin is fo thick, that thefe are not ealily diftinguifhed before that is pulled off. The foramina of the noftrils are two, and are placed in the very fummit of the fnout, one on each fide. The body is long and cylindric ; in fome fpecies there are three fins, in others two, in others only one. The fpecies of Murana enumerated by Artedi, are thefe: I. The fimple- coloured Murisna, with the lower jaw longeft. This is the common eel. 2. The Murmr.a, with the upper edge of the back fin black. This is the conger, or fea eel. The iris of this fifh is white ; that of the common eel is red. 3. The Murana with a fharp fnout, variegated with white fpots, and with the edge of the back fin black. This is the myrus of the antients, and the flat-tailed fea ferpentofthe later writers. 4. The cylindric-bodied Mur&na, with no fin at the tail. This is the common fea ferpent of authors ; it grows to five foot in length. 5. The cylindric, flendcr, and fpottcd Murana, with a rounded cufpidated tail, with no fin to it, This is the fpotted fea-feipent of authors. 6. The Murana with no pecforal fins. This is the fifh which all authors call the Murxna, Artedi only extending that word as a generical name to the other fpecies. Artedi, Gen. Pile. 19. According to IVillughby, the Murana is a fifh of the anguilli- form or eel-like clafs. Its body is broad, and its fnout pointed, and of a flatted figure. It is variegated in colour with a dufky
 * brown