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for keeping up the flame, ami consequently render the heat lessintense. With regard to the flame proper to be chosen, Mr.Bergman directs a slender candle, either of wax or tallow, (lig.16,) with a cotton wick, k l. The burned top must be cut atsuch a length, that the remainder may be bent a little. Theorilice, g (lig. 14,) is to he held above and near to this arch, per-pendicular to i o (lig. 16,) and the air equally expressed. Theflame being forced to one side by the violence of the blast,exhibits two distinct figures; the internal ligure is conical,blue, and well-delined ; at the apex of this cone, the most violentheat is excited ; the external flame, l o, brownish, vague, andindetermined ; having much less heat at its extremity, o, thanthe interior flame has. If, instead of the breath, or of commonair, oxygen gas be employed, the heat will be much more in-tense. The canal throughout the pipe, but particularly the holeat the small end, must be made very smooth, so that there beno inequalities in it; else the wind will be divided, and conse-quently the flame made double. That blow-pipe is to be reckon-ed the best, through which can be formed the longest and mostpointed flame from off a common-sized candle. These blow-pipes are commonly made of brass or silver. There ate two dif-lerent kinds of matter made use of for the support of those sub-stances usually examined by the blow-pipe : tlie one is charcoalof fir, or beech, cut into the form of a parallelepiped : the other asilver, or, which is better, a golden spoon, fitted with a woodenhandle. The former is generally used.

BLUBBER is the name of the fat of large sea-animals, as wellas of whales, whereof train-oil is made. It is properly the adepsof the animal : it lies immediately under the skin, and over themuscular flesh, in the porpoise it is firm and full of fibres, andinvests the. body about an inch thick. In the whale, its thicknessis usually six inches ; but about the under lip, it is two or threefeet thick. The whole quantity yielded by one of these animalsordinarily amounts to 40 or 50, sometimes SO cwt. or even more.

BLUE is one of the seven colours into which the rays of lightdivide when refracted through a glass prism. Lor an account ofthe particular structure of bodies by which they appear of a bluecolour. See Optics. The principal blues used in painting are-Prussian blue , bice, Saunders blue, azure, or smalt, verditer, &c.for the preparation of which see Colour-Making. In dyeing,the principal ingredients for giving a blue colour, are indigo andwoad. See Dyeing.

Blue Ashes, [ Ccndre bleu, Fr.] by corruption, Saunders blue,are much used in water colours, and some are very lively; but inoil they grow greenish, being of the nature of verdigrise. Theyare found in the form of a soft stone, in places where there are cop-per mines ; and water only is used in levigating them, to reducethem to a fine powder. This kind of blue ought to be used inworks to be seen by candle-light, as in scene-painting, for thougha great deal of white is mixed with it, it appears very beautiful,notwithstanding it has a greenish cast.

Bluk-Bice is a colour of good brightness, next to Prussian blue ,and also a colour of a body, and will flow pretty well in the pencil.

Blue , for the painting or staining of glass—1'ake fine white sandtwelve ounces, zaffer ami minium of each three ounces; reducethem to a fine powder in a bell-metal mortar; then putting thepowder into a very strong crucible, cover it and lute it well, andbeing dry calcine it over a quick fire for an hour; take out thematter and pound it: then to sixteen ounces of this powder addfourteen of nitre powder; mix them well together, and put theminto the crucible again ; cover and lute it, and calcine for two hourson a very strong fire.

Blue, Flanders, is a colour seldom used but in landscapes,being apt to turn green. The French call it cendre verte, or greenashes.

Blue, to dye skins.—Boil elder-berries or dwarf elder; thensmear and wash the skins therewith, and wring them out ; thenboil the berries as before in a solution of alum-water, and wet theskins in the same manner once or twice ; dry them, and they willbe very blue.

Blue, to make Japan . Take gum-water, and white lead, asufficient quantity ; grind them well upon a porphyry : then takeisinglass size, and the finest and best smalt, sufficient quantities ;mix them well, and add, of the white-lead, before ground, somuch as may give it a sufficient body. Mix all these together tothe consistence of a paint.

Blue John, among miners, a kind of mineral which is fabricatedinto vases and other ornamental figures. It is of the same qualitywith the cubical spar, with respect to its fusibility in the lire, ftloses its colour, ami becomes white in a moderate heat: the weightof a cubic foot of the bluest kind is 3180 ounces, and that ot theleast blue is 3140 ounces.

Blue-Mantle, in heraldry, the title of a pursuivant at arms.

Blue Mountain, a high and extensive ridge of the Apalachianmountains which is about 4000 feet high, and extends throughthe N. parts ot New Jersey into Pennsylvania , as far as the Sus-quehanna.

Blue Nuns, [filles blues,'] a title of the order of those of theannunciatiou.

Blue, Prussian, or Berlin Blue , is considerably in useamong painters, though inferior to the ultramarine blue. It is amodeni invention, and was discovered by accident, about the be-ginning of the last century. A chemist of Berlin, havingsucees-ivelythrown upon the ground sevtnfl liquors from his laboratory, wassurprised to see it suddenly stained with a most beautiful colour.—Recollecting the liquors lie had thrown oil each other, he made asimilar mixture in a vessel, and produc ed the same colour. liecjid not publish his process, but prepared and sold his blue, whichwas substituted for ultramarine. The account of it was first pub-lished in the Berlin Memoirs, 1710; but without the descriptionof its process. See Colour-Making.

Blue, Saxon, a dye made by dissolving indigo in oil of vitriol,by w liich the indigo becomes of a much more lively colour, and isextended to such a degree that it will go very far iii dyeing. SeeColour-M aking.

Blue, Stone or Powder, used in the washing of linen, is tiresame with smalt, either in the lump or powdered.

Blue, Turnsole, is used in painting on wood. It is made ofthe seed of that plant, by boiling four ounces of turnsole in a pintand a half of water wherein lime has been slacked.

Blue , Ultramarine, [q. d. beyond sea, from its being firstbrought into Europe out of India and Persia, ] one of the richestand most valuable colours, used in painting, is prepared fromLapis Lazuli , by first calcining the stone in an iron pot; then-grinding it very fine on porphyry ; then mixing it up with a pastemade of wax, pitch, mastich, turpentine, and oil; and at lastwashing the paste well in clear water, to separate the colouringpart from the rest, which precipitates to the bottom, in form of asubtle, beautiful, blue powder. The water is then poured off,and the powder is dried in the sun. Mr. Boyle gives a method tomake a fine blue colour, nearly equal to ultramarine, by collect-ing the blue corn-bottle, or Centaurea cyanus , which aboundsin almost every corn-field : it has two blue tints ; the one pale inthe larger outward leaves, the other deeper, which lies in the mid-dle of the tlower; by rubbing the last, while fresh, so much asto express the juice, it will yield a beautiful' and unfading colour.

On the same day that the flower is gathered, the middle shouldbe separated from the extremities, and when a quantity of thejuice is obtained, a small addition of alum will produce a perma-nent clear blue, which, in the opinion of many persons, is notinferior to ultramarine.

Blue, a line one from Mr. Boyle.—Take the blue leaves of rue,and beat them a little in a stone-mortar with a wooden pestle ; thenput them, in water, juice and all, for fourteen days or more, wash-ing them every day till they are rotten; and at last beat them andthe water together till they become a pulp, ami let them dry in thesun. This is a fine blue for shading.

Blue , Indigo. This makes the strongest shade for blues, andis of a soft warm colour, when it has been well ground, and washedwith gum-water, by means of a stone and a muiler.

Blue , Lacmus, or Litmus. This is a beautilul blue, and willrun in a pen as free as ink. It is made of lacmus, and preparedthus; take an ounce of lacmus, and boil it in a pint of small beer-wort, till the colour is as strong as you would have it; then pouroil' the liquor into a gallipot, and let it cool for use. This affordsa beautiful colour, has extraordinary elfeets, and is a holding co-lour; if it he touched with aquafortis, it immediately changes toa line crimson, little inferior to carmine.

BLUEING, is the art of commmicating a blue colour to-differ-ent kinds of substances. Laundresses blue their linen with smalt;dyers, their stuffs and wools with woad or indigo.

Blueing ot Metals i» nenormed bv beating them in the fire

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