Encyclopaedia Americana: a popular dictionary of arts, sciences, literature, history, politics and biography, brought down to the present time : including a copious collection of original articles in American biography : on the basis of the seventh edition of the German Conversations-Lexicon (Volume 4).

Date:
1830-33
Catalogue details

Licence: Public Domain Mark

Credit: Encyclopaedia Americana: a popular dictionary of arts, sciences, literature, history, politics and biography, brought down to the present time : including a copious collection of original articles in American biography : on the basis of the seventh edition of the German Conversations-Lexicon (Volume 4). Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    CRAWFISH-CREAM OP TARTAR. find them inhabiting excavations of con- siderable depth along the borders, or a short distance within the current of the stream, at the bottom of which they lie hid. In the spring of the year, by cau- tiously approaching, and remaining quietly on tlie margin of such a stream, we may see the crawifish uidustriously bringing from the lower part of their caves the dirt accumulated there; and this enables us to comprehend the mamier in wliich they originally made their retreats. Upon the two great claws, folded towards each oth- er, and thus forming, with the fiont of the body, a sort of shelf, the dirt is carefiiUy brought to the surface, and thrown down just where the cmTent will sweep it away. As the substances thus brought up are verj' light, it requires a veiy gentle move- ment of the animal to avoid spilling, or rather washing off his lading; and he tJierefore rises in the gentlest and most cii'cumspect manner. We can testify to tlie patience with which this labor is con- tinued, as, witli the view of obser\'ing the operation, we have often quietly pushed in the earth from the edge of the water, which they as often have toiled on to remove. It is upon these fi-esh-water species that the observations have been made, relative to the re-production of limbs or claws \iolently broken off. But a short time elapses before a gro\\th or vegetation occurs at the stump or broken })art, and a new limb, similar to the origi- nal, though sometimes rather smaller, is soon formed. This facility of re-])roduc- tion is found to extend throughout the crustaccous class. Fresh-water crawfish ai'e regarded by many as furnishing a del- icate dish for the table, though their small size, and the trouble of collecting a suffi- cient number of them, are great obstacles to their being extensively employed in this way. They are preyed upon by various animals, especially by certain birds, whose long bills are adapted to picking them out from the bottom of their dens. Crater, Caspar, a Dutch painter, bom in 1582, at Antwei-p, was a pupil of Raph- ael Coxie, and became, by the study of nature, one of the greatest historical and poili'ait pahiters. At the Spanish court in Brussels, he painted the portrait of the cardinal Ferdinand, brother of the king, and received a pension. He established himself in Ghent, where he constantly executed works for the court. He labored with industry and perseverance till his 86th year. When Rubens saw his finest painting in the refectory of the abbey of Affleghem, he cried out, Crayer, Crayer, nobody viill ever surpass thee! The city of Ghent alone had 21 altar-pieces by him. In Flanders and Brabant are many of his works, and some of his pictures are in the public collections at Vienna and Munich. His paintings are praised for fidehty to nature, excellent drawing, and a coloring approaching the manner of Van- dyke. The latter was his friend, and took his likeness. Crayer died in 16C9. Crayons ; a general name for all color- ed stones, eartlis, or other minerals and substances used in designing or painting in pastel, whether they have been beaten, and reduced to a paste, or are used in their primitive consistence, after being sawn or cut into long, narrow slii)S. The sticks of diy colors which go under this name, and which are cemented into a friable mass, by means of gum or size, and sometimes of clay, afford a veiy simple means of apply- ing colors, being merely nabbed upon pa- per, after which the shades ai-e blended or softened by means of a stump or small roll of leather or paper. The drtiAvings require to be protected by a glass covering, to save them from being defaced, unless some means have been adopted to fix them, so that they may not be liable to be rubbed off'. This may be done by brush- ing the back of the j)aper with a strong solution of isinglass, or by passing the drawing tlirough a powerful press, in con- tact with a moist paper. Cream of Tartar {potassfB snperiar- tras; crcmor taiiuri]. This salt exists in grapes and in tamarinds. The dregs of whie also contain a considerable quantity of it. Cream of tartar contains a very considerable i:)roportion of super-tartrate of potassa, about seven or eight hundredths of tartrate of lime, and a small (juantity of silica, albumen, iron, &c. It is insoluble in alcohol, but may be dissolved in 15 parts of boiling and 60 of cold water. It may be rendered much more soluble by mixing with it a certain quantity of bo- racic acid or borate of soda, Avliich ren- ders the cream of tartar soluble in its own weight of cold water, and in the half only of this menstruum when boihng. This preparation is known by the name of solu- ble cream oftmiar. Its aqueous solution is soon decomposed by the contact of the air. It is obtained by dissolving in boil- ing water the common tartar—a white or reddish crjstalline matter, which foims on the internal sides of the vessels in which wine has been kept—mixing with it some clay, which precipitates the coloring mat- ter, arid then permitting the Uquor to crystallize. The potion of this substance