132 LAMPEEY are burned in iron pots or furnaces with very limited access of air. The dense smoke pro- duced by the combustion is conveyed into chambers hung with sacking, upon the surface of which the lampblack is deposited. It is scraped or shaken off from time to time, and sent to market without further preparation. The illustration shows the arrangement of the apparatus generally used. A cylindrical brick chamber 10 or 15 ft. in diameter, with a conical roof, has a small opening at the top to main- tain a sufficient draught to cause the clouds of smoke to ascend toward the upper part of the chamber. A cone of sheet iron hangs within the cylinder, having a small hole in its apex, through which the gases pass upward. At the side and base of the chamber is a kind of fur- nace, above the fire in which is placed a pan containing resinous or fatty matters, which are heated to a point sufficient to convert them into vapor, and then the vapor undergoes suffi- cient combustion to be deprived of its hydro- gen, while most of the carbon is unconsumed. The smoke ascends into the chamber, and is mostly deposited upon the hanging canvas or sacking, and upon the inner surface of the iron cone, from which it falls after a certain thick- ness is collected. The cone is so held by a chain and pulley that it may be lowered, which operation scrapes the lampblack off the sack- ing. The lampblack thus prepared is not pure charcoal, as it is mingled with resinous and bituminous substances, with ammoniacal and other matters. By heating it to redness in a vessel permitting no access of air, the im- purities are driven off, and an almost pure im- palpable charcoal powder remains. Other kinds of black are used in the arts, such as Spanish black, which is made from cork ; vine black, made from vine tendrils ; and peach black, made from peach kernels, which has a bluish color. German or Frankfort black, used in making copperplate ink, is said to be made by carbonizing a mixture of grape and wine lees, peach kernels, and bone shavings. LAMPREY, a cyclostome or marsipobranch fish of the family petromyzonidcs (hyperoartia, Miiller), and genus petromyzon (Linn.). This order, with the myxinoids, constitutes the class of myzonts of Agassiz. The blood is red, the heart distinct, the branchial artery without a bulb and furnished at the base with two valves ; the body smooth, cylindrical, and vermiform ; mouth anterior, gills fixed, and eyes distinct ; the single olfactory cavity opens above by an external foramen, leading to a blind canal not communicating with the mouth through a per- forated palate as in the myxinoids ; thorax cartilaginous, sustaining the branchial appara- tus composed of rib-like strips descending on each side beneath the skin, with seven external spiracles, opening from the fauces into a sub- 03sophageal tube, having a posterior caecal ex- tremity. These are the first fishes in which there is a distinct brain enclosed in a cartila- ginous cranium ; there are two dorsal fins, the posterior joined with the caudal, and mere folds of skin with scarcely perceptible rudi- mentary rays ; pectorals and ventrals absent ; the cephalic cartilage is undivided ; there is a spout hole on the head, and a spiral valve in the intestine ; there is no oviduct nor seminal duct. The jaws are absent, but the circular mouth, tongue, and pharynx are armed with conical or crescentic sharp teeth of indurated albumen. The gills are seven little fixed bags, each having its proper artery, its opening into the sub-oesophageal tube, and its external fora- men by which the water passes out. The old genus petromyzon has been subdivided into six, according to the shape and arrangement of the teeth. The common European lamprey, or lamprey eel as it is often called (P. marinus, Linn.), attains a length of more than 3 ft. ; the color is yellowish marbled with brown. Having no air bladder and being destitute of lateral fins, they are usually found near the bot- tom, and to avoid being carried away by the cur- rents they attach themselves to stones by means of the tongue, which acts like a sucking piston in the circular mouth, whence the names of petromyzon and cyclostomes ; in the same man- ner they attach themselves to larger fishes, which they devour ; by means of the apparatus above described, respiration may be carried on independently of the mouth, the branchial cur- rents passing from one series of openings to the other across the sub-oesophageal tube. The intestine is small and nearly straight ; the eggs are laid late in the spring, the milt and roe es- caping by a membranous sheath communica- ting with the abdominal cavity. They ascend rivers from the sea to spawn. They are very generally distributed in Europe from the Medi- terranean to the arctic waters, ascending the rivers in spring ; at this season great numbers are caught, their flesh being considered a delicacy. The food of the lamprey consists of any soft animal matter, especially the flesh of fishes to which they attach themselves. The river lam- prey or lampern (P. fluviatilis, Linn.) is a smaller fish, and confined to fresh or brackish water; the length is from 12 to 18 in., and the color bluish olive above and silvery below. Great numbers were formerly caught in the Thames, Severn, &c., and sold to the Dutch for bait in the turbot fishery. This and the pre- ceding species are very tenacious of life, living several days out of water. The most common of the American species is the P. America- nus (Lesueur), growing about 2 ft. long ; the color is olive brown above, with blackish brown confluent patches, and beneath uniform dull brown. This is not uncommon in the rivers of New England and New York, espe- cially near their mouths ; it likes best shallow rapid streams with pebbly bottoms, in which it builds circular nests 3 or 4 ft. in diameter and a foot or two high, bringing stones in the mouth varying from the size of a hen's egg to that of the fist. They ascend high falla by clinging to the rocks, after suddenly dart- 1
