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plaftic power, or peculiar modus of attraction, by which the particles before fufpended in the water are brought to- gether under a peculiar form. This power in general fo ex- erts itfeif over the harder particles of matter fuftained in the water, as to arrange them into the form of an hexangular pyramid, terminating an hexangular column of four, five, 'or more times its length. Thus is the common rock cryf- tal formed; and when this power is unmolefted, the co- lumns of this body are carried to a great fize. Thefe cryftais are of different t'ranfparences and colours^ as the pure matter, of which they are compofed, is more or iefs difengaged from the mixture of foreign particles ; or as thofe, or other fubftances, are found capable of imparting their tinctures, or other qualities to them: but when the plaftic particles are more numerous, there feems reafon to believe that thefe very plaftic particles, before they are fixed, are fubject to the controul and direction of any fixed plaftic particle, within the verge of whofe activity they happen to move. Notwithstanding which, after they are once fixed, they exert their own plaftic powers, and, in conjunction with the firft plaftic principle, govern the future concre- tion in fuch manner, as to form a feemingly irregular cryf- tal, though compofed of two more regular cryftais. Thefe cryftalline concretions exert a ftrong attraction on many metallic fubftances, fo as frequently to contain lead, copper, and other metals* in very confiderable quantities, embodied in them.
The waters of mines are* bbfide cryfral, impregnated alfo with a great quantity of fulphureo-faline particles, and thefe are in lbme of a vitriolic, and in others of an arfenical na- ture. The firft of thefej when pure, concrete into white cubes, refembl'ing grains of filver ; while the other, or ar- fenical fulphur, concretes into yellow cubesj refembling grains of pure gold. Both thefe concretions, whether fingle, or in large confufed duffers, are called by the miners mini- dick. The fulphureo-faline principle of concretion feems of the fame nature with the plaftic power in the formation of cryftais ; and thefe bodies, like the others* are in the fame manner found fometimes fimple, fometimes compound. On the fides of thefe the concretion may always be obterved forming itfeif into threads, which in three fides run in dif- ferent directions, but are always fimilar in the oppolite fides. Philof. Tranf. N°40i, p. 403.
Load is alfo ufed for nine d'lfhes of ore, each difh being about half a hundred weight. Houghton's compl. Miner in the Explan. of the Terms.
Majier Load, among miners, See Master load.
LOADSTONE {Cycl.)-* Armed Loadstone, one that is capped, oafed, or fet in iron or fteel, in order to make it take up a greater weight, and alfo to diftinguifh its poles readily.
The armour of a load/lone, in figure of a right angled pa- rallelogram, confifts of two thin pieces of fteel or ironj in figure of a fquare, having a thlcknefs proportional to thi goodnefs of the ftone j for if a weak ftone has a ftrong ar- mour, it will produce no effect ; and if the armour of a ftrong loadjione be too thin, it will not produce fuch an ef- fect, as if the armour were thicker. A convenient thick- nefs for the armour is found by filing it thinner and thin- ner, until you find its effect to be the greateft poflible. The armour of a fpherical loadjione confifts of two fteel fhells fattened to one another by a joint, and muff: cover ' a good part of the convexity of the itone. This muft be alfo filed away by degrees, until the effect: of the loadjione is found greateft.
It is very wonderful, that the armour of a loadjione will fo much augment its effect, that good ftones, after they are armed, will lift up above one hundred and fifty times more than before. And even indifferent ones, that weigh only three ounces unarmed, will, when armed, lift more than feven pounds.
LOAM, (Cycl.) in natural hlftory, the name of a clafs of fomle bodies, the characters of which are thefe. They are compound earths compofed of diflimilar particles, hard, ftift\ denfe, harfh, and rough to the touch, not eafily ductile while moift, readily diffufible in water, and ufually com- pofed of fand and a tough vlfcid clay. Of this clafs there are two genera. 1. The thraiiftom'tftbes ; and 2. the glifchromiclbes. The firft are compofed of fand and a lefs vifcid clay, and are of a friable or crumbly tex- ture. The fecond are compofed of fand and a more vifcid clay, and are of a more tough and vifcid texture. Hill's Hilt, of FofT. See the articles Thraustomicthes and Glischromicthes.
LOBLOLLY, a fea-faring difh, otherwifc called burgoo. See the article Burgoo.
LOBS, in mining, are ftcps that afcend or defcend within the mines, as ftairs up to and down from a chamber. Hough- ton's compl. Miner in the Explan. of the Terms.
LOBUS echinatus, in the materia medica, a name hy which fome authors have called the bonduch, or Bczoar nut. Ger, Emac. p. 1554-
LOCH, [Cycl.) in the materia medica, a name given by Avi- fenna, and cthers 3 to the gum lac- They call it alfo hi-
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hm and henhni, and are too apt to confound it with tfifl cancamum, fandarach, and other gums, with which they made their feveral forts of varnifli. See Cancamum. LOCHE, or^LocHE, a name ufed in fome parts of Eng- land for the muftela, cailed in other places, particularly in Cornwall, the ivhijlle fijh. Wllugbby's Hift. Pifc. p. 121. See Mustela. LOCHIA {Cycl.)— The Hux of the lochia, or of blood and humors from the uterus, about the time of parturition, is of two kinds ; the one called legitimate, which happens after the exclufion of the foetus, at its proper time ; the other abortive, which attends mifcarriages, and does not indeed follow them, but either precedes, or happens immediately ui the act of abortion, and that ufually in a very violent and terrible manner. The legitimate is alfo often too co- pious. Signs of it. The legitimate loch'wl flux is an excretion of blood from the genitals for eight, ten, twelve, or fourteen, days after child-birth, and fometimes for a longer time than that. During the firft days, pure blood, grumous, and coagulated, is difcharged, or at leaft a fluid coloured with blood; after the fourth or fifth day, this difcharge is attended with a_ difagreeable, and fometimes with a plainly foetid Knell 5 in the fucceeding days the humor becomes lefs'bloody, and more and more yelltiwilh 1 , and after this it gradually becomes pale and watery, till it lofes all colour and fmell : all this while alfo the flux becomes more and more moderate in quantity, till at length it wholly ceafes of itfeif. This is the natural ftate of this flux j but if the fecundines are too long retained, or if a part of them be torn off and left in the uterus, then the flux frequently exceeds its due bounds, and many pains and fpaftic motions are felt about the uterus, and throughout the abdomen. In the Ischial fluxes attending abortions, the blood ufuallv flows out gently and moderately before the act, then it comes on, during the exclufion of the fcetus, with great violence. Sometimes alfo, when violent paffions of the mind have preceded, it comes on with all this violence at the firft attack, before the fcetus is excluded : this is follow- ed by the fcetus^ or falfe conception, which ever is in the uterus, and this is attended ufually with faintings, and with violent pains in the belly. Perfons fubject to frequent abor- tions, have lefs trouble and pain with them than others, and the lochial flux is with them in lefs quantity. The', too great flux of the lochia is a thing of dangerous Confequence* and the perfons principally fubject to it are thofe of plethoric habits, . and fuch as are fubject to violent paffions; fuch as are ufed to much wine, or other ftrong liquors, and to high feafoned foods, as alfo fuch as have omitted bleeding at the proper times during their being with child, and fuch as have been accuftomed to too co- pious fluxes of the menfes. In cafes of abortions, thofe are moft of all fubject to immoderate fluxes of them, who have not been duly treated, or properly purged and clean fed, after a former lying in. The principal occafions of large fluxes of the lochia after child-birth, are cither a plethoric habit, or the ufe of violent medicines to promote delivery* or the retention of part of the fecundines in the uterus. Prognojlicks from it. The flux of the lochia, when moderate and regular, is of the utmoft benefit to the perfon, and the fuppreifion of it is ever attended with danger. This is, of all other fluxes of blood, the moft fubject to exceed the ufual quantity ; and in abortions, after the third month of pregnancy, is ufually greater than in parturitions at the full time. When this flux is immoderately great, the pa- tient's ftrength is confirmed by it in a very little time; and when it is not thus violent for a continuance, but returns, after fhort intervals, with violent effects, it is a fign that the womb is not properly cleanfed, and the perfon is after- wards frequently either barren, or fubject to repeated abor- tions. In cafes of a threatned abortion, when there has once been a copious difcharge of blood, there fhculd be no attempt made to retain the fcetus in its place. Method of treating. When the flux of the lochia is moderate, it requires no afliftance from the phyfician, but nature is to be left to her own courfe; if they flow too immoderately, the fame means are to be ufed as in cafes of violent fluxes of the menfes. The medicines which have power to quiet . the violent emotions of the blood are to be often repeated, fuch are nitre, the alkaline abforbents, as crabs eyes, and the like, and a little cinnabar : if thefe are infufficient, re- courfe is to be had to the milder aftringents, fuch as the crocus mortis antimonialis, and tincture of fait of fteel, and. the decoction, or extract of the common yarrow. The abortive flux of the lochia is to be treated in the fame manner with the too violent one attending parturition at the full time. The abortion is always to be haftencd, and the fce- tus, mole, or whatever, to be taken out as foon as poffible, when the flux becomes violent, left the patient faint and perifh under it. The way to prevent an immoderate flux of the lochia in parturition, is to bleed often during the time of pregnancy, and if neceftary, this may be done even juft before delivery. The proper ligatures on the belly, after the exclufion of the fcetus, are alio of great fen-ice ia
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