PIOZZI. 45 union was comfortable. Thrale had a house in Southwark and an estate at Streathani, near Croydon. Dr. Johnson became acquainted with Mrs. Thrale in 1764, and for sixteen years spent much time at Streatliam Park. He was there usually from Saturday till .Monday, and for months during the sunuuer. The memorable friendship was of great value to him. By society his eccentricities in dress and manners were toned down: and his disposition to gloom was neu- tralized l)y the presence of a vivacious and charm- ing woman. In his whole career this is the only bright period. Thrale died in 1781, and three years later his widow married Gabriel Piozzi, an Italian musician. Piozzi was a man of talent and lionor, but .Johnson could brook no divided allection. He never again saw the friend who had so long ministered to his comfort. Im- mediately after the marriaf;e. the Piozzis went to Italy, returning to England in 1787. They lived at Streatham till 1705, when they settled at Bachycraig. Flintshire. Wales, an estate Jlrs. Piozzi inherited from her father. They after- wards built a villa, named Brynhella. on the C'lwy. There Piozzi died in 1809. Mrs. Piozzi pass'ed her last years mostly at Bath, Clifton, and Penzance. iShe died. May 2, 1821. Mrs. Piozzi's only valuable contributions to literature are Anecdotes of the Late Samuel Johnson (17S(i) and Letters to and from the Late 8. Johnson (1788). Of her occasional verse, the best is Three Waniiiifis, published in the Miscel- lanies of Mrs. Williams (1766), containing also .Johnson's Fountains, a prose tale, of which the heroine is Mrs. Thrale. While at Florence in 178.5 Mrs. Piozzi associated with the Delia Cruscans and wrote for the Florence iJiscellani/. after- wards ridiculed by William Gifford (q.v.). Con- sult her Aulohiofiraphi/. Letters, and Literari/ Kemains, ed. by Hayward (London and Boston, 1861): Mangi'n, Pio~xiana (London, 18.3.3); Seeley, Mrs. Thrale, life and selections from writ- ings "(London and New York, 1891) : Glimpses of Italian Society in the Eifihtcenth Century, from the Journey of Mrs. Piozzi, by the Countess Cesareseo (London, 1892) ; Boswell's Life of Johnson (ib., 1791); and the Diary of Mme. d'Arblay (ib., 1842-46). PIP. The hero of Dickens's Great Expecta- tions, who on the death of his unknown benefac- tor, the convict Magwitch, instead of gaining the wealth he had anticipated, is reduced to poverty. PIP. A disease of poultry. See Roup. PIPA ( NeoLat., from the native name of the Surinam toad). A South American frog (family Pipidoe). the 'Surinam tflad' { f'ipa .Americana), celebrated for its extraordinary method of carrying its eggs in the skin of the back. It is a peculiar, ugly-looking creature. The whole skin is covered with small tvdiereles, and is dark in color on the upper surfaces, but whitish on the under side of the body. Every- where the .skin bears papilhe, each with a little horny spike, and many with a poison gland at the base. The back of the female is furnished with numerous cells or pouches, in which the eggs are hatclied and the young iindergo all their transformations. It was not imtil the process was observed by Bartlett. who watched captive specimens in London ( Proceedinys of the Zoolofji- cal Society, London. 1896, p. .59,5) that the method of placing the eggs in this curious nursery PIPE. was understood. Late in April, 1896, Bartlett noticed that the male pipa toad.s were becoming very lively, and were constantly heard uttering their metallic, ticking call-notes. On examining them, two of the males were observed clasped tightly around the lower parts of the bodies of females, the hind parts of the males extend- ing beyond those of the females. On the follow- ing morning the keepers arrived in time to wit- ness the mode in which the eggs were deposited. The oviduct of the female protruded from her body more than an inch in length, and the blad- der-like protrusion, being retroverted, passed under the belly of the male on to her own back. The male appeared to press tightly upon this protruded l)ag, and to squeeze it from side to side, apjiarently pressing the eggs forward, one by one, on to the back of the female. By this movement the eggs «ere spread with nearly uniform smoothness over the whole surface of the back of the female, to which they became firmly adherent. When the operation was com- pleted the males left their places on the females, and the enlarged and projected oviduct gradually disappeared. The eggs are produced in the early part of the rainy season, when these highly aquatic frogs have plenty of water about them, and at that time it is very diflicult to capture them. In the dry season these frogs collect in swamps and ditches^ and sometimes come clo.se to or into houses. Consult Gadow, Amphibia and Reptiles (London, 1901). PIP'CHIN, Mks. A character in Dickens's Domhey and Son. She kept an establishment for young children at Brighton, where Paiil was sent. PIPE. An implement for smoking tobacco, opium, etc. See Tobacco-Pipe. PIPE (AS. pJpe, from ML. pipa, pipe, from Lat. pipire, pipiare, to pipe, onomatopoetic in origin). An artificial closed channel, or con- duit, for liquids, air, or gases, often under high pressures. Pipes are composed of a great va- riety of materials, according to the uses to which they are to be put and the cheapness of the various materials in a given locality. Lead Pipe.s are known to have been used at Babylon, Rome, and Pompeii, and, like all lead pipe imtil recent times, were made from sheets of lead bent to a ])ear-shaped section, with the horizontal joint welded or soldered. About the beginning of the sixteenth century the casting of lead pipes was begun in Eng- land, the process having been inented by Koliert Brooke. In 1790 an F,nglish patent for draw- ing lead pipe was granted, and a machine was built for pressing lead pipe through dies. As the larger sizes of lead pipe have to be very thick to retain their shape and withstand high pressures, and on account of the high cost of lead pipe and for other reasons, such pipe is but little used now in diameters of over 2 inches or so, but it is nuxde up to 4 inches, and, though rarely, to 6 or 8 inches. At the other extreme, it is made as small as ^j inch, inside diameter. Modern Icail pipe is pressed through dies in a contimuius length. The molten lead is poured into a cylindrical hole in a hydraulic press. In the centre of the hole is a metal rod or core the same diameter as the pipe. When the metal begins to solidify the press rises and forces the
