Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/37

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the world. This country, indeed, was famous before his time for this produce ; and the Greeks have celebrated it ; and Sophocles, in particular, fays, that no flour is fo white, or fo good, as that of Italy. The corn of this country has, however, loft much of its reputation fince that time ; and the reafon of this feems to be, that the whole country being full of fulphnr, alum, vitriol, marcafites, and bitumens, the air may have, in time, affected them fo far, as to make them diffufe themfelves through the earth, and render it lefs fit for vegetation; and the taking fire of fome of thefe in- flammable minerals, as has fometimes happened, is alone Sufficient to alter the nature of all the land about the places where they are. Defland. Trait. Phyf.

The flour of England, though it pleafes by its whitenefs, yet it wants fome of the other qualities valuable in flour ; the bread that is made of it is brittle, and does not hold toge- ther, but after keeping a few days becomes hard and dry, as if made of chalk, and is full of cracks in all parts ; and this muft be a great difadvantage in it when intended for the fervice of an army, or the like occaiions, where there is no baking every day, but the bread of one making muft necefla- rily be kept a long time.

The flour of Picardy is very like that of England, and after it has been kept fome time, is found improper for making into pafte or dough. The French are forced either to ufe it immediately on the grinding, or elfe to mix it with an equal quantity of the flour of Bretany, which is coarfer but more unctuous and fatty; but neither of thelc kinds of flour keep well.

The flour of alm'oft any country will do for the home con- fumptton of the place, as it may be always frefh ground ; but the great care to be ufed in felecting it is in order to the fending it abroad, or furnifhing ihips for their own ufe. The faline humidity of the fea air ruits metals, and fouls every thing on board, if great care be not taken in the pre- ferving them. This alio makes the flour damp and mouldy, and is often the occafion of its breeding infects, and being wholly fpoiled.

The flour of fome places is conftantly found to keep better at fea than that of others ; and when that is once found out, the whole caution needs only be to carry the flour of thole places. Thus the French find that the flower of Poi- tou, Normandy, and Guienne, all bear the fea carriage ex- tremely well, and they make a confiderable advantage by carrying them to their American colonies. The choice of flour for exportation being thus made, the next care is to preferve it in the mips ; the keeping it dry is the grand confideration in regard to this ; the barrels in which it Is put up ought to be made of dry and wcll-feafoned oak, and not to be larger than to hold two hundred weight at the moll. If the wood of the barrels have any fap remaining in it, it will moiften and fpoil the flour ; and no wood is fo proper as oak for this purpofe, or for making the bins and other veftels for keeping flour in at home, iince, when once well dried and feafoncd, it will not contract humidity after- wards. The beach wood, of which fome make their bins for flour, is never thoroughly dry, but always retains fome fap. The fir will give the flour a tatte of turpentine j and the afli is always fubjecT: to be eaten by worms. The oak is preferable becaufc of its being free from thefe faults ; and when the feveral kinds of wood have been examined in a proper manner, there may be others found as fit, or poflibly more fo than this for the purpofe. The great teft is their having more or lefs fan. See the articles Flour and Wood.

Meal worm. See the article Worm.

MEAN (Cyd.) — MeanAw/w/j 1, in aftronomy. See the article Anomaly, Cyel.

Mean j „ J _. » C in aftronomy, is when the mean place

of the fun is in 5 qS^ I with the man place of the

moon in the ecliptic. See the articles Conjunction and Opposition, Cyd. Mean dijhnoe of a planet from the fun, in aftronomy, is the right line drawn from the fun, to the extremity of the conju- gate axis of the ellipfis the planet moves in ; and this is equal to the femitranfverfe axis, and is fo called becaufe" it is a mean between the planets greateft and leaft diftance from the fun.

Mean Motion, in aftronomy, that whereby a planet is fup- poicd to move equally in its orbit, and is always propor- tional to the time.

MEASURE [Cyd.)— We have lately had fome accurate com- panions between fome of the French weights and meafures, and thole of England, the refult of which is, i. The Pans halt tone, as let off on the ftandard kept in the Royal ooc iety, contains of EngHfn inches, by the fame ftandard, 3» ^55- whence it appears, that the Englifh yard and foot is, u. ihe Paris half toife and foot, nearly as 107 to 114.; for as 107 to 114, fo is 36*038.35514. J' j.^ c ' 3a, '' s tWo marc, or fixteen ounce weight, weighs y'H -r y Sra ' ns 756 ° s whence ft appears, that the Eng-

Mh I roy pound of twelve ounces, or 5760 grains, is to the 1 aris two rmrc. or fixteen ounce weight, as 16 to 21 ; that

the Paris ounce weighs Englifh Troy grains 472.5 ; and that confequently the Englifh Troy ounce is to the Paris ounce, as 64 is to 63.

3. The Englifh avoirdupois pound weighs Troy grains 7004; whence the avoirdupois ounce, whereof fixteen make a pound, is found equal to 437.75 Troy grains. And it follows, that the Troy pound is to the avoirdupois pound, as 88 to 107 nearly ; for as 88 to 107, fo is 5760 to 7003. 636 ; that the Troy ounce is to the avoirdupois ounce, as 80 to 73 nearly ; for as 80 to 73, fo is 480 to 438. And, laftly, that the avoirdupois pound and ounce, is to the Paris two marc weight and ounce, as 63 to 68 nearly; for as 63 to 68, fo is 7004 to 7559.873.

4°. The Paris foot, exprelled in decimals, is equal to 1. 0654 of the Englifh foot, or contains 12. 785 Englifh inches. Phil. Tranf. N°. 465. Seel. 5.

MEAT (Cyd.)— Meat, in the manege. See the article Dry Meat.

MEB, or Sea Me b, in zoology, the name of a water bird of the Iarus or gull-kind, which is all over of a dufky grey on its upper part ; its head is blackifh at the top, and the beak is red. The legs are fhort and black, and the wings very long, reaching beyond the tail when folded.

MECAXOCHITL, in the materia medica, the name of the piper longum humilius, or fmall American long pepper. Dale, Pharm. p. 286.

MECHANICAL (Cyd.)— Mechanical Force. See the ar- ticle Force, appendix.

Mechanical Operation of Medidnes. Seethe article Medi- cine.

MEDAL (Cyd.)—hnpreffiom of Medals. A very eafy and elegant way of taking impretfions of Medals and coins, not generally known, is this : Melt a little ifinglafs glue, made with brandy, and pour it thinly over the medal, fo as to cover its whole furface ; let it remain on for a day or two, till it is thoroughly dry and hardened, and then taking it off, it will be fine, clear, and hard as a piece of Mufcovy glafs, and will have a very elegant impreflion of the coin. Shaiv's Lectures, p, 430.

Sulphur is fometimes ufed to take off imprcflions of Medah, coins, &c. The method is this : Having made a ledge of clay about the work, whofe imprcflion is delired, and care- fully oiled the whole, gently pour brimftone melted in a co- vered veflel, to prevent its firing upon the metal. About the edge of this mould make a border of clay, as before, and lightly oil the internal furface of both ; then gradually put into it, to the thicknefs of about a quarter of an inch, a mixture made up with calcined alabafter and water, to the confiftence of ftifF honey. This foon growing hard, may be taken out of the mould, and gives figures of the coin or Me- dal. Boyle's Works abr. vol. 1. p. 151. A method fome- what different is defcribed in the article Brimstone. We have an eafy method of procuring the true imprcflion or figure of Medals and coins, by Mr. Baker in the Phil. Tranf. N°. 472. Seer. 13.

Take a perfect and fharp impreflion In the fineft black feal- ing-wax, of the coin or Medal you defire. Cut away the wax round the edges of the impreflion ; then with a pre- paration of gum-water, of the colour you would have the picture, fprcad the paint upon the wax impreflion with a fmall hair pencil, obferving to work it into all the finking or hol- low places, thefe being the rifing parts of the Medal ; and the colouring muft be carefully taken from the other parts with a wet finger. Then take a piece of very thin poft paper, a lit- tle larger than the Medal, and moiften it quite through. Place. it on the wax impreflion, and on the back of the paper lay three or four pieces of thick woollen cloth or flannel, of about the fame iize. The impreflion, with its coverings, fhould be placed between two fmooth iron plates, about two inches fquare, and one tenth of an inch thick. Thefe muft be care- fully put into a fmall prefs, made of two plates of iron, about five inches and an half long, one inch and a half wide, and half an inch in thicknefs, having a couple of long male fcrews running through them, with a turning female fcrew on each, to force the plates together. Thefe being brought evenly to- gether, by means of the fcrews, will take off a true and fair picture of the Medal; which, if any deficiencies mould appear, may cafily be repaired with a hair pencil, or pen, dipped in the colour made ufe of.

If a relievo only be defired, nothing is neceffary, but to take a piece of card, or white pafte-board, well foaked in water, then placing it on the wax mould, without any colouring, and letting it remain in the prefs for a few minutes, a good figure will be obtained.

This Method of taking off Medals, &c. is convenient, and feems much more fo than the feveral inventions ufually pra£tifed in fulphur, plafter of Paris, paper, C5V, wherein a mould muft be formed, either of clay, horn, plafter, or other materials, which require a good deal of time and trou- ble.

Some take impreffions on paper from the Medals themfelves, by parting them through the rolling- prefs, and colouring them afterwards ; but this is not only more difficult, but does great, injury to the Medals, by impairing the Iharpnefs of their moft

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