DIAZ DE NOVAES, BARTHOLOMEU (ft. 1481-1500), Portuguese explorer, discoverer of the Cape of Good Hope, was probably a kinsman of Joao Diaz, one of the first Portuguese to round Cape Bojador , and of Diniz Diaz, the discoverer of Cape Verde • In 1478 a Bartholomeu Diaz, probably identical with the discoverer, was exempted from certain custom ary payments on ivory brought from the Guinea coast. In 1481 he commanded one of the vessels sent by King John II. under Diogo d'Azambuja to the Gold Coast. On Oct. 1o, 1486, he received an annuity of 6,000 reis from King John for "services to come" ; and some time after receiving the money he left Lisbon with three ships fully manned and equipped to carry on the work of African exploration which had been so greatly advanced by Diogo Cao (1482-86).
Passing Cao's farthest point near Cape Cross (in the modern German South-west Africa and in 21 ° 5o' S.), he erected a pillar on what is now known as Diaz Point, south of Angra Pequena or Luderitz bay, in 26° 38' S.; of this fragments still exist. From this point (according to De Barros) Diaz ran 13 days southwards, in a compar atively high southern latitude, considerably south of the Cape. Failing, after several days' search, to find land, the Portuguese turned north, and so struck the south coast of Cape Colony at Mossel bay (Diaz' Bahia dos Vaqueiros), half way between the Cape of Good Hope and Port Eliza beth (Feb. 3, 1488). Thence they coasted eastward, passing Algoa bay (Diaz' Bahia da Roca). The officers and men now began to insist on return, and Diaz could only persuade them to go as far as the estuary of the Great Fish river. Here, however, half way between Port Elizabeth and East London, the north-easterly trend of the coast became unmistakable : the way round Africa had been definitely laid open by the Portuguese explorer.
On his return Diaz perhaps named Cape Agulhas after St. Brandan; while on the southernmost projection of the modern Cape peninsula, whose remarkable highlands doubtless impressed him as the practical termination of the continent, he bestowed, says De Barros, the name of Cape of Storms (Cabo Tormentoso) ; this name was changed by King John to that of Good Hope (Cabo da Boa Esperanca). Some authorities, however, make Diaz himself give the Cape its present name. After touching at the Ilha do Principe (Prince's island, south-west of the Cameroons) as well as at the Gold Coast, he returned to Lisbon in Dec. 1488. He had discovered 1, 26o m. of hitherto unknown coast ; and his voyage, taken with the letters soon afterwards received from Pero de Covilhao (who by way of Cairo and Aden had reached Malabar on one side and the "Zanzibar coast" on the other as far south as Sofala, in 1487-88) was rightly considered to have solved the question of an ocean route round Africa to the Indies and other lands of South and East Asia.
No record has yet been found of any adequate reward tendered to Diaz for his great achievement ; on Cabral's voyage of 15oo it has been recorded he was indeed permitted to take part in the discovery of Brazil (April 22), and thence should have helped to guide the fleet to India ; but he perished in a great storm off his own Cabo Tormentoso, now known as Good Hope, and which he discovered in 1488. As Galvano says, he was allowed to see the Promised Land, but not to enter in.
See Joao de Barros, Asia, Dec. I. bk. iii. ch. 4. (ed. A. A. Grillo and G. A. Grillo, i866, etc.) ; Duarte Pacheco Pereira, Esmeraldo de situ orbis (see Raphael Basto, Introduction to his edition, 1892 ; also ed. A. da Silva Dias, 1905) . A marginal note, probably by Christopher Columbus himself, on fol. 13 of a copy of Pierre d'Ailly's Imago mundi, now in the Colombina at Seville, fixes Diaz's return to Lisbon in Dec. 1488. The writer says he was present at Diaz's interview with the King of Portugal, when the explorer described his voyage and showed his route upon the chart he had kept. See also the Journal of the First Voyage of Vasco de Gama (Hakluyt Society, ed. E. G. Ravenstein, 1898) ; F. Lopes de Castanheda, Historia (bk. i., Coimbra 1551) ; A. Galvao, Descobrimentos (Discoveries of the World) (Hak luyt Society, 1862) ; E. G. Ravenstein, "Voyages of Cao and Dias" in Geographical Journal (vol. xvi., in organic chemistry, compounds containing the characteristic group –N :N–, generally, although not invariably, joined to only one carbon atom, the other valency being satisfied either by (I) an electronegative or acidic radical, as in the diazonium salts; (2) an oxygen atom in the diazohydroxides and diazo-oxides, or (3) a nitrogen atom in the diazo-amino-compounds (diazo-amines). The diazo-compounds are not only of scientific interest but of considerable industrial importance, for they are essential to the manufacture of azo-dyes—the largest group of synthetic colouring matters. (See DYES, SYNTHETIC.) These diazo-compounds were discovered by P. Griess (1858), who pursued this investigation while engaged as chemist in the brewery of Allsopp & Co. of Burton-on-Trent.
The diazotization of aniline and other similarly constituted aromatic primary amines is carried out on a manufacturing scale as a necessary step in the production of colouring matters. More than I,000 tons of para-nitraniline are diazotized annually in the formation on cotton fibre of "para-nitraniline red."