BIAS. 207 DIASTASE. summer of 14S7 with three yessels. One, a slave vessel, was left at a harbor near the limit of previous exploratiun, and then Dias began his long voyage along the unknown African coast, to a part of which he gave the expressive name of "Hell.' Just after Xew Years Day, 1488, he was caught by a storm which drove him southward for thirteen days, until his crews, fresh from the tropics, began to suffer from the cold. As soon as the storm subsided Dias steered eastward, but, not meeting with land for several days, lie turned his prow northward, .fter sailing 'M blagues he sighted higli numntains, and anchored, Feb- ruary 3, 14SS, in the modern !Mossel Bay, in Cape Colony. Finding that the coast ran cast and west, he followed it to Algoa Ha.v, where the coast began to trend more toward the northeast. Dias proceeded as far as the nioutli of the Great Fish River, but was induced by the complaints of his .sailors to turn back. It was probably on May 10 that he passed Cape Agulhas, the actual southernmost point of Africa, and a day or two later he .saw the striking Table Mountain and the cape which he is commonly said to have named Cabo Tormentoso (Cape of Storms), in memory of the perilous experiences with which it was associated, but which the Portuguese King rechristened Cabo da Boa Esperanza, the Cape of Good Hope, though, according to Christopher Co- lumbus, who was present at the royal interview, Dias himself proposed the name. In December Dias reached home, with the news that the point of Africa had been turned, and that the way lay open toward the spice markets of the East. He had added 1200 miles of coast to the knowledge of European sailors and geographers. Between 1490 and 149.5 Dias was in command of a vessel engaged in the African trade. When, in 1497, Vasco da Gama was dispatched to complete Dias's discovery of the way to the East, the latter ac- companied him as far as the Cape Verde Islands, and thence sailed to the Gold Coast to trade. Three years later he commanded one of the ships in Cabral's fleet. Leaving Brazil in May. 1500, Dias perished in a storm which wrecked his ves- sel. Consult E. J. Ravenstein, "Vo.vages of Cao and Dias. London Geographical Journal (1900). DIAS, de'ash. Goxc.vlves Antoxio ( 1S-2.'?-(56) . A Brazilian poet, bom at Caxias. He was educated at the university of Coimbra. Portugal, and for a time practiced law at Maranh.ao, Brazil. He was afterwards professor of history in the College of Dnm Pedro II. at Rio de Janeiro. His works in- clude a report, Uracil e Oceania: several papers of value on the migrations of the South American Indian tribes: and a number of volumes of poetrv, among them the series Primeiros Cantos (1840), Segiinrlos Cantos (1848), and UUimos Cantos. DIAS, Hexriqitc (?-lf)01). A Brazilian sol- dier of African blood. I)orn in PernamI>uco. He fought with the Portuguese against the Dutch under Gen. Matias de All)uquerque (10.33). and did valuable service. He defended Arraial do Bom .Te«us, and upon its f;ill was permitted lv the Dutch to escape, and rejoined llie Portuguese army. His brave conduct caused him to he made commander-in-chief of the negro forces, and he was rewarded with the cross of the Order of Christ. In 1045 he rose against the Spaniard.?, and incited the districts of Sergipe, Sao Fran- 'isco, and Alat'oas to revolt. For the next ten years he fought continuously, but after the Dutch and independent Spaniards were beaten, Dias was not remembered and promoted with the other generals who fought in Pernambuco. He died in poverty, although his name has always been given to a negro regiment commanded by one of its own race. DI'ASPORE (Gk. SiaoTropd, diaspora, a scat- tering, from 6iaa-ilpeiv, diaspeirein, to scatter, from (lid, dia, through + a-eipea; speirein, to scatter). A hydrated aluminum oxide that crystallizes in the orthorliombic s,vstem, is trans- l)arent to translucent, and usually white or light gray, though sometimes of a brownish or yellowish color. It occurs with corundum and emery in dolomite and olilorite schist. This mineral is found in granular limestone with emery, in the Ural region, in Hungary, Sweden, Asia Minor, and in the United States at the einer^'-mines of Chester, Mass., where it occurs in large plates in crystals, and is also found with massive corundum near Franklin, ilacou Countv, X. C. DI'ASTASE (Gk. Staffraa-is, diastasis, sep- aration, from diuTTdvai, diistanai, to separate, from Sid, dia, apart -|- ia-rdi/ai, histanai, to stand ) . An enzjme found in both animals ahd plants, which has the power of converting starcli into a sugar. It has also been called amylase, and in the saliva is known as ptyalin. In plants, where it is practically universal, diastase occurs in two modifications, which have their parallels also in animals, viz. secretion diastase and translocation diastase. These differ in their distribution, their mode of action on starch- grains and starch paste, the optimum tempera- ture for activity, etc. Translocation diastase is the more widely distributed of the two, being formed by fungi and bacteria, and in leaves, shoots, storage organs, and pollen-grains, as well as in the seed. Its function seems to be to make possible the translocations of carbo- hydrate food, temporari!,v or permanently stored as starch, by digesting it into a soluble sugar. Translocation diastase is therefore of the utmost importance in plant nutrition. Secretion di- astase is formed by special secreting cells in the embryo of seeds, especially in grasses, and plays its chief role in germination by making available the food stored as starch in the seed. Transloca- tion diastase digests and liquefies starch paste slowly, and erodes starch-grains uniforml.v at the surface or in the centre until they disappear. Secretion diastase liquefies starch paste rapidly and corrodes starch-grains by forming irregular pits, which, penetrating the grain in various directions, deepen and widen until it falls to pieces. Translocation diastase is most .active at 45° to 50* C. (113° to 122° F.), secretion diastase at 50° to 55° C. Both are destroyed at 70° C. (158° F.). Diastase cannot be obtained in a pure state; and because its composition has not yet been ascertained, no test for purity can be established. It may be oljtained by crushing or grinding the tissue containing it, e. g. malt, and extracting it for twent.v-four hours with three or four times its bulk of Mater or weak alcohol. The liquid may be filtered off and the various substances dissolved along with the diastase may be par- tially eliminateil by adding about three volumes of absolute alcohol, collecting on a filter the pre- cipitate formed, washing it with absolute alcohol
