D1A 



DIA 



of soda and of diamond powder being ex- 

 posed to a very strong heat) that it had 

 suffered any chemical change from the 

 action of the alkali ; for though a minute 

 portion of earthy matter appeared to be 

 produced, this might probably b derived 

 from the various agents which were em- 

 ployed in the experiments. (Essays, vol. 

 ii.p. 118.) 



DIAMOND, in the glass trade, an in- 

 strument used for squaring the large 

 plates or pieces; and, among glaziers, for 

 cutting their glass. 



These sorts of diamonds are differently 

 fitted up ; that used for large pieces, as 

 looking-glasses, &c. is set in an iron fer- 

 ril, about two inches long, and a quarter 

 of an inch in diameter; the cavity of the 

 ferril being filled up with lead, to keep 

 the diamond firm : there is also a handle 

 of box, or ebony, fitted to the ferril, for 

 holding it by. 



DIAMOND, in heraldry, a term used for 

 expressingthe black colourin the achieve- 

 ments of peerage. Guillim does not ap- 

 prove of blazoning the coats of peers by 

 precious stones instead of metals and co- 

 Jours ; but the English practice allows it. 

 Morgan says the diamond is the emblem 

 of fortitude. 



DIAN/E arbor, or ARBOR lunte, in che- 

 mistry, the beautiful crystallizations of 

 silver, dissolved in nitrous acid, to which 

 some quicksilver is added ; and so called 

 from their resembling the trunk, branches, 

 leaves, &c. of a tree. This elegant ar- 

 rangement, however, of the particles of 

 silver is not peculiar to this state or men- 

 struum, since copper filings dropped into 

 the solution of silver in aqua fortis is 

 found to have the same effect, when view- 

 ed by the miscroscope : nay, the silver 

 ores are frequently found ramified in the 

 same manner. 



DIANDRIA, the name of the second 

 class in Linnaeus's sexual system, consist- 

 ing of hermaphrodite plants, which, as 

 the name imports, have flowers with two 

 stamina or male organs. The orders in 

 this class are three, derived from the 

 number of styles or female parts. Most 

 plants, with two stamina, have one style, 

 as jassamine, lilac, privet, veronica, and 

 bastard alaternus. Vernal grass has two 

 styles ; pepper three. 



DIANTHERA, in botany, a genus of 

 the Diandria Monogynia class and order. 

 Natural order of Personatae. Acanthi, 

 Jussieu. Essential character : corolla 

 ringent; capsule two-celled, bursting 

 with an elastic nail ; stamina each a pair 

 of alternate anthers. There are twelve 



species, of which D. americana is a low 

 herbaceous plant, with a perennial root, 

 which sends out several weak stalks 

 about four inches long. The leaves are 

 hairy, sessile, and of a dark green colour, 

 and an aromatic odour. The flowers are 

 produced from the side of the stalks in 

 small spikes, and are in shape and colour 

 very like those of clinopodium. They 

 come out in July, but rarely produce 

 seeds in England. It is a native of Vir- 

 ginia. This species is also called Justi- 

 cia americana, and Justicia pedunculosa ; 

 the last specific name given from the long 

 peduncles which support the flowers. 



DIANTHUS, in botany, a genus of the 

 Decandria Digynia class and order. Na- 

 tural order of Caryophyllei. Essential 

 character; calyx cylindric, one-leafed, 

 with four scales at the base ; petals five, 

 with claws ; capsule cylindric, one-cell- 

 ed. There are thirty species. These 

 beautiful plants are chiefly herbaceous ; 

 some few however are suffruticose. 

 Most of them are hardy, and perennial 

 or biennial; some of the smaller wild 

 sorts only are annual ; stalks annual, from 

 one to three feet in height ; leaves oppo- 

 site, narrow, entire ; flowers terminating, 

 many aggregate, some solitary, or several 

 together, but distinct. This numerous 

 genus includes the sweet-williams, carna- 

 tions, and pinks, with their several varie- 

 ties ; for a full and complete account of 

 which we refer the reader to Martyn's 

 edition of Millar's botany. 



DIAPASON, in music, a musical in- 

 terval, by which most authors who have 

 wrote upon the theory of music, use to 

 express the octave of the Greeks. See 

 OCTAVE. 



The diapason is the first and most per- 

 fect of the concords ; if considered sim- 

 ply, it is but one harmonica! interval, 

 though if considered diatonicaUy, by tones 

 and semi-tones, it contains seven degrees, 

 viz. the three greater tones, two lesser 

 tones, ajid two greater semi-tones. 



The interval of a diapason, that is, the 

 proportion of its grave sounds to its acute, 

 is duplicate, '. e. as 2 : 1. 



DIAPENSIA, in botany, a genus of the 

 Pentandria Monogynia class and order. 

 Natural order of Precise. Convolvuli, 

 Jussieu. Essential character ; corolla sal- 

 ver-shaped ; calyx five-leaved, imbricate, 

 with three other leaflets; stamens placed 

 on the tube of the corolla; capsule three- 

 celled. There is but one species, viz. D. 

 lapponica, a native of the mountains of 

 Lapland, among stones covered with 

 moss ; also in Norway. 



