Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/660

 TOP

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Tooth-drawings however wrong in many cafes, yet is certainly right and neceffary in others, i. In children for the remov- ing their lacteal or deciduous Teeth, for when thefe are left too long in their fockets, they difplace the new ones and turn them awry. 2. In infants it is alfo neceffary to draw fuch Teeth as grow out of the palate, or out of improper parts of the mouth, and are placed fo as to impede their fpcaking or fuck- ing. 3. In the Tooth-ach proceeding from a Tooth's being carious, and giving way to no medicines, drawing is the lait refort, and is abfolutely neceffary. 4. Thofe Teeth ought to be drawn which by their irregular figure and pofition lacerate the gums and lips, and cannot be brought into fhape by the file. And laftly, it is fometimes necelfary to draw a Tooth for the curing a fiftula, or ulceration of the gums near the roots of the Teeth.

The regular method of drawing them is this : If the Tooth is in the lower jaw, the patient muft be feated on a low feat, or on the floor, and if in the upper jaw, he muft be placed on a high ffool or table ; then the proper inftrument is to be felected, and the Tooth carefully drawn as a nail out of a piece of wood. But this muft never be done while the gums are inflame'd, fwelled, or otherwife diftempered. Hei/ler's Surgery, p. 456. See alfo Faucbard ? s Ghimrgien Dcntiite.

Wolf- Tooth. See the article Wolf.

Toom-Wort, in botany. Seethe article Plumbago.

TOP (Cyci.) — Top of a Ship, around frame of boards lying upon the crofs-trees near the head of the mafts, here they furl or loofe the Top-fail, &c.

Top-Armours, in a fhip of war, are a kind of cloths hung about the round- Tops of the mafts for fhow ; and alfo to hide the men which are m the Top in a fight, who lie there to fling ff.ink-pots, &c. or to fire fmall fhot down on the enemy in cafe of boarding.

Top-Mq/is, in a fhip arc four, which are made faft and fettled unto the heads of the main-maft, foremaft, mizzen-maft, and bow-fprit refpectively.

Top -Gallant- Mafts, in a {hip are two, viz. main-Top-gallant- majl, and fort --Top- gallant- majl, which are fmall round pieces of timber, fet on their refpective Top-mafls ; on the top of which mafts are fet the flag-ftaffs, on which the colours, as flags, pendants, &c. hang.

1 QP-Ropes, in a fhip, are thofe with which the Tap-majls are fet or ftruck. They are received through a great block, which is feized on one fide under the cap, and then are reeved through the heel of the Top-maft, where is a brafs fhiver placed athwart {hips ; after this they are brought up and faftened on either fide the cap with a ring : the other part of them comes down by the ties, and fo is reeved into the knight-head ; and when it is to be heaved, it is brought to the capftan. Thefe Top- ropes belong only to the main and fore-maft.

Top-Sail-Lifts, on board a fhip. See the article Lifts.

Top-Sails, and Top-Gallaut-Saih, in a fhip, are thofe be-

^ Jonging to the Tfip-mafts, and 7<?/>-galIant-mafts.

1 oP-a-Starboard, on board a fhip, the word of command to hale upon the larboard lift.

Top the Yard-Arms, on board a fhip, a word of command to make the yards hang higher or lower. See the article Ya r d.

1 OPAN, in zoology, a name by which fome have called the horned-beaked Indian raven, more ufually known by the name of the rhinoceros -bird, Worm, Muf. p. 113. See the arti- cle Rhinoceros-A/j.

TOPAZ, Topazius. The name given by the moderns to a gold -coloured gem, called by the antients the chryfolite, or gold-coloured gem.

This is a very valuable and beautiful gem, when pure and in its moft perfect ftate, but fuch are very rare; and the lefs per- fect ones common among our jewellers are of little beauty or price.

The Topaz is never found very large ; the far greater num- ber of the oriental ones are as fmall as the head of a large pin, and it is but here and there one, which arrives at the fixth of an inch diameter, and very few indeed exceed that ftandard. TheAmerican ones are fomewhat larger than thefe, and the Eu- ropean are the largeft of all ; but of the leaft value. It is al- ways found in a pebble^like form ; roundifh or oblong, and flatted on one fide, and of an irregular and uneven furface, but ufually bright and of a good natural polifh, unlefs where fouled by accidents. It is never found in a columnar orcryf- tal-like form, notwithftanding that our dealers in gems carry on a large trade with what they call Topazes, which are of this fhape : but all thefe when brought to the wheel are found to be no more than common cryftals, accidentally tinged to a yellow colour, as is very common for the cryftals and fpars to be, in and about mines, from an admixture of me- talline particles ; and almoft all the common Topazes worn in rings are of this falfe kind.

The colour of the Topaz is ever a pure yellow; but, like the other gems, it has this in very different degrees : the fineft Topazes are of a true and exact gold-colour, and are of great fplendour; but they vary from this in degree, up to the deepeft fafTron-colour, and down to that of the paleft amber. The fineft Topazes are of equal hardnefs with the ruby and fapphire, and are fecond only to the diamond ; from this they degenerate down to the hardnefs of a garnet, and yet lower ; ?-

but In all the genuine Topazes, even the very meaneft are, when brought to the mill, found to be much harder than cryftal. The fineft Topazes have a luftre at leaft: equal to any o- em except the diamond ; but the others are but dead and heavy : the oriental ones divefted of their colour, by putting them in the fire, make a very clofe counterfeit. The Topaz is found in the Eaft and Weft-Indies, and in many parts of Europe : the oriental are greatly fuperior to thofe of any other part of the world ; and the American are not much better than the German. The fineft gem of this kind ever known, is in the poffeffion of the Great Mogul ; its weight is faid to be 157 carrats, and its value more than twenty thou- fand pounds. Hill's Hilt of Foff. p. 598. feq. Counterfeit Topaz. To counterfeit the oriental Topaz inpafie: Take cryftal prepared two ounces, ordinary minium or red lead feven ounces ; put thefe into a crucible luted, and bake them twenty-four hours in a potter's kiin. If the mafs is not fufficiently clear and fine, cover it up again and give a fecond. baking, and it will come out of a fine Topaz-zolona. Neri's Art of Glaffi p. 13 r. TOPE, in ichthyology, an Englifh name for a fpecies of the fqualus according to the Artedian fyftem, diftinguifhed from the other fquali, by the noftrils being placed extremely near the mouth, and by certain foramina, or apertures near the eyes. It is the fiih called by the antients ya\i®- xwty galeus cams and canicida. See the article Galeus Cams. TOPIARIA, in botany, a name by which fome authors have called the acanthus, or bear's breech, a plant common in the gardens of the curious. Ger. Emac. Ind. 2. TOPICS {CycL) — Topics are fuch medicines, as fay the fmallnefs and mobility of their particles, attended for the moft part with a gentle acrimony, are able to make their way into the fubitancc of the parts to which they are applied, without erod- ing or wounding any of the folide; and thence are juitly called penetrating Topics.

it may be a queftion how Topics m medicine act. It is commonly laid that this or that medicine penetrates the pores; hut the ideas annexed to fuch expreffions do not feem very diftinct. Writers on this fubjedt have feldom been at the pains to tell us what pores they mean. We have an effiiy on this fubject in the Medic. Efl". Edinb. Vol 2. Art. 4. by Dr. Armftrong, who thinks that the effects of fuch medicines are not owing to their particles entering the orifices of the abforb- ent veins ; nor to the opening of the exhalent veffels on the furface of the body by thefe medicines ; nor will he allow the particles of penetrating Topics to force their way through the coats of the veftels ; but he fuppofes, that fubtile medicines are conveyed by the exhalant veilels of the fkin, to thofe parts of the fmaller arteries, where the circulation is choaked by obftruction. Topic, in rhetoric. See the article Locu?. TOPPING the Lifts, aboard a fhip, the fame as haling the top- fi\i]-iifts, and therefore they fay top-a-Jlarboard, or top-a-port, that is, hale upon the ftar-board, or larboard lift. See the ar- ticle Litts. TORCH- Thijlle, Cereus, in botany, a fpecies of plants belong- ing to theG?6?2/j-genus. Sec the article Cactus, Append. This plant confifts of a fingle ftem or body, twenty, thirty, or more feet high, and about five inches in diameter. It is of an angular figure, and armed with clufters of fharp firm fpines, growing from tubercles placed along the ribs. The flowers, when open, are of the fizeof a large rofe, and con- fift of forty or more petals; the outer ones purplifh or greenifh, the inner ones white.

It is a native of Surinam, and many parts of fouth America. It has gotten the name Torch-thijlle, from its being much ufed for Torches.

This plant is frequent in our ftoves among the curious in exo- tic vegetables, but it fo rarely flowers, that many who have kept feveral fpecies of it in their ftoves for their whole lives, have not happened to fee it. Dr. Trew gives a particular ac- count of the flowering of one of thefe plants, at Nuremberg, in the year 1730; which may be agreeable to the curious, who have not themfelves feen it.

The plant which flowered there was a branch (even years before feparated from another Cereus in the fame garden, which had never flowered. It had in this time grown to be fix foot high, and thirteen inches thick : it had feven angles near the bafe, eight in the middle, nine near the top. Its upper part appeared of a bluifh green, from a dufty matter it was covered, with ; its lower part was of a fine grafs-green, and the down of the prickles was whitifh near the top, and every where elfe brown. On the fifth of September, within an inch of its top, their appeared a round knot growing out of the trunk, this increafed in fize very faft and grew out horizontally, on the fourteenth of the fame month, it was eight inches long, and plainly fhewed the rudiments of a flower, tho' as yet doled up, and fome elegant ftains of green, purple, and white were vifible on it.

The fame evening the flower began to open, and at midnight was fully expanded, it was then fix inches in diameter, and was of a ftrong but not plcafant fiftell. After midnight it began to contract ; it grew lefs by half an inch in a few hours, and remained of this fize till the next day at noon ; it then foon

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