(from dio twice, and oikia a house or habitation) two houses. The name of the 2nd clas in Linnaeus's sexual method, consisting of plants, which having no hermaphrodite flowers, produce male and female flowers on separate roots. These latter only ripen seeds; but require for that purpose, according to the sexualists, the vicinity of a male plant; or the affusion, that is, sprinkling, of the male dust. From the seeds of the female flowers are raised both male and female plants. The plants then in the clas diecica are all male and female; nor hermaphrodite, as in the greater number of classes; nor with male and female flowers upon one root, as in the clas monoeica of the same author. See Botany, p. 430.

Diogenes of Apollonia, in the island of Crete, held a considerable rank among the philosophers who taught in Ionia before Socrates appeared at Athens. He was the scholar and successor of Anaximenes, and in some measure rectified his master's opinion concerning air being the cause of all things. It is said, that he was the first who observed that air was capable of condensation and rarefaction. He passed for an excellent philosopher, and died about the 450th year before the Christian era.

Diogenes the Cynic, a famous philosopher, was the son of a banker of Sinope in Pontus. Being banished with his father for coining false money, he retired to Athens, where he studied philosophy under Antiphanes. He added new degrees of austerity to the sect of the Cynics, and never did any philosopher carry so far a contempt for the conveniences of life. He was one of those extraordinary men who run everything to extremity, without excepting even reason itself; and who confirm the saying, that "there is no great genius without a tincture of madness." He lodged in a tub; and had no other moveables besides his staff, wallet, and wooden bowl, which last he threw away seeing a boy drink out of the hollow of his hand. He used to call himself a vagabond, who had neither house nor country; was obliged to beg, was ill clothed, and lived from hand to mouth: and yet, says Athenian, he took as much pride in these things as Alexander could in the conquest of the world. He was not indeed a jot more humble than those who are clothed in rich apparel, and fare sumptuously every day. He looked down on all the world with scorn; he magnificently censured all mankind, and thought himself unquestionably superior to all other philosophers. Alexander one day paid him a visit, and made him an offer of riches or anything else: but all that the philosopher requested of him was, to stand from betwixt the sun and him. As if he had said, "Do not deprive me of the benefits of nature, and I leave to you those of fortune." The conqueror was so affected with the vigour and elevation of his soul, as to declare, that "if he was not Alexander, he would choose to be Diogenes;" that is, if he was not in possession of all that was pompous and splendid in life, he would, like Diogenes, heroically despise it. Diogenes had great presence of mind, as appears from his smart sayings and quick repartees; and Plato seems to have hit off his true character when he called him a Socrates run mad. He spent a great part of his life at Corinth, and the reason of his living there was as follows: As he was going over to the island of Aegina, he was taken by pirates, who carried him into Crete, and there exposed him to sale. He answered the crier, who asked him what he could do, that "he knew how to command men:" and perceiving a Corinthian who was going by, he showed him to the crier, and said, "Sell me to that gentleman, for he wants a master." Xeniaes, for that was the Corinthian's name, bought Diogenes, and carried him with him to Corinth. He appointed him tutor to his children, and entrusted him also with the management of his house. Diogenes's friends being desirous of redeeming him, "You are fools," (said he); "the lions are not the slaves of those who feed them, but they are the servants of the lions." He therefore plainly told Xeniaes, that he ought to obey him, as people obey their governors and physicians.

Some say, that Diogenes spent the remainder of his life in Xeniaes's family; but Dion Chrysostom affirms that he passed the winter at Athens, and the summer at Corinth. He died at Corinth when he was about 90 years old: but authors are not agreed either as to the time or manner of his death. The following account, Jerom says, is the true one. As he was going to the Olympic games, a fever seized him in the way; upon which he lay down under a tree, and refused the assistance of those who accompanied him, and who offered him either a horse or a chariot. "Go you to the games," (says he), "and leave me to contend with my illness. If I conquer, I will follow you: if I am conquered, I shall go to the shades below." He dispatched himself that very night; saying, that "he did not properly die, as get rid of his fever." He had for his disciples Onetrites, Phocion, Stilpo of Megara, and several other great men. His works are lost.

Diogenes Laertius, so called from Laerta in Cilicia where he was born, an ancient Greek author, who wrote ten books of the Lives of the Philosophers, still extant. In what age he flourished, is not easy to determine. The oldest writers who mention him are Sopater Alexandrinus, who lived in the time of Constantine the Great, and Hesychius Milefus, who lived under Justinian. Diogenes often speaks in terms of approbation of Plutarch and Phavorinus; and therefore, as Plutarch lived under Trajan, and Phavorinus under Hadrian, it is certain that he could not flourish before the reigns of those emperors. Menage has fixed him to the time of Severus; that is, about the year of Christ 200. From certain expressions in him some have fancied him to have been a Christian; but, as Menage observes, the immoderate praises he bestows upon Epicurus will not suffer us to believe this, but incline us rather to suppose that he was an Epicurean. He divided his Lives into books, and inscribed them to a learned lady of the Platonic school, as he himself intimates in his life of Plato. Montaigne was so fond of this author, that instead of one Laertius he wishes we had a dozen; and Volland says, that his work is as precious as gold. Without doubt we are greatly obliged to him for what we know of the ancient philosophers; and if he had been as exact in the writing part, Diogenes, as he was judicious in the choice of his subject, we had Diomedia, been more obliged to him still. Bishop Burnet, in the preface to his Life of Sir Matthew Hale, speaks of him in the following proper manner: "There is no book the ancients have left us (says he), which might have informed us more than Diogenes Laertius's Lives of the Philosophers, if he had had the art of writing equal to that great subject which he undertook: for if he had given the world such an account of them as Gaddens has done of Peirefs, how great a stock of knowledge might we have had, which by his unskilfulness is in a great measure lost? since we must now depend only on him, because we have no other and better author who has written on that argument." There have been several editions of his Lives of the Philosophers; but the best is that printed in two volumes 4to, at Amsterdam, 1693. This contains the advantages of all the former, besides some peculiar to itself: the Greek text and the Latin version corrected and amended by Meibomius; the entire notes of Henry Stephens, both the Casaubons, and of Menage; 24 copper-plates of philosophers elegantly engraved: to which is added, The History of the Female Philosophers, written by Menage, and dedicated to Madam Dacier. Besides this, Laertius wrote a book of Epigrams upon illustrious Men, called Pammeterus, from its various kinds of metre: but this is not extant.

Diomedia, in ornithology, a genus belonging to the order of anseres. The bill is straight; the superior mandible is crooked at the point, and the lower one is truncated; the nostrils are oval, open, a little prominent, and placed on the sides. There are two species, viz. 1. The exulans, has pennated wings, and three toes on each foot. It is the albatross of Edwards; and is about the size of a pelican. These birds are found in the ocean betwixt the tropics and at the Cape of Good Hope. They are also often seen in vast flocks in Kamtschatka, and adjacent islands, about the end of June, where they are called Great Gulls; but it is chiefly in the bay of Penchinenis, the whole inner sea of Kamtschatka, the Kurile isles, and that of Bering; for on the eastern coasts of the first they are scarce, a single straggler only appearing now and then. Their chief motive for frequenting these places seems to be plenty of food; and their arrival is a sure prefiguration of shoals of fish following. At their first coming they are very lean, but soon grow immensely fat. Are very voracious birds, and will often swallow a salmon of four or five pounds weight; but as they cannot take the whole of it into their stomach at once, part of the tail end will often remain out of the mouth; and the natives, finding the bird in this situation, make no difficult matter of knocking it on the head on the spot. Before the middle of August they migrate elsewhere. They are often taken by means of a hook baited with a fish; but it is not for the sake of their flesh that they are valued, it being hard and unfavourable, but on account of the intestines, a particular part of which they blow up as a bladder, to serve as floats to buoy up their nets in fishing. Of the bones they make tobacco-pipes, needle-cases, and other useful things. When caught they defend themselves stoutly with the bill. Their cry is harsh and disagreeable, not unlike the braying of an ass. The breeding Diomedes, breeding places of the albatross, if at all in the northern hemisphere, have not yet been pointed out; but we are certain of their multiplying in the southern, viz., Patagonia and Falkland islands: to this last place they come about the end of September or beginning of October, among other birds, in great abundance. The nests are made on the ground with earth, are round in shape, a foot in height, indented at top. The egg larger than that of a goose, four inches and a half long, white, marked with dull spots at the bigger end; and is thought to be good food, the white never growing hard with boiling. While the female is sitting, the male is constantly on the wing, and supplies her with food: during this time they are so tame as to suffer themselves to be shovelled off the nest while their eggs are taken from them; but their chief destruction arises from the hawk, which, the moment the female gets off the nest, darts thereon, and flies away with the egg. The albatross itself likewise has its enemy, being greatly persecuted while on the wing by the dark grey gull called *kua*.

This bird attacks it on all sides, but particularly endeavours to get beneath, which is only prevented by the first settling on the water; and indeed they do not frequently fly at a great distance from the surface, except obliged so to do by high winds or other causes. As soon as the young are able to remove from the nest, the penguins take possession, and hatch their young in turn. It is probable that they pass from one part of the globe to another according to the season; being now and then met with by different voyagers at various times in intermediate places. The food is supposed to be chiefly small marine animals, especially of the mollusca or blubber clams, as well as flying fish. 2. The demersa, has no quill-feathers on the wings; and the feet have four toes, connected together by a membrane. It is the black penguin of Edwards, about the size of a goose, and is found at the Cape of Good Hope. It is an excellent swimmer and diver; but hops and flutters in a strange awkward manner on the land, and, if hurried, stumbles perpetually, and frequently runs for some distance like a quadruped, making use of the wings instead of legs, till it can recover its upright posture; crying out at the same time like a goose, but in a much louder voice. It is said to clamber some way up the rocks in order to make the nest; in doing which, has been observed to assist with the bill. The eggs are two in number, white, as large as those of a duck, and reckoned delicious eating, at least are thought so at the Cape, where they are brought in great numbers for that purpose. At this place the birds are often seen kept tame; but in general they do not survive the confinement many months.