TI A i, KITH- 



DIAMOND 



7-'J 



due to dialect speakers themselves, ami \\ln-n -< 



due, us in limn- - jioriii-, it in I..,, apt In I..- unduly 



mi\ed up with modern received speech. Nuturally, 

 the bom diali-i-i -|..-.iker is not a literary man, an 

 the writer of dialect works inevitably i-. Some of 

 tin- best pi.-i-r-, iif ( 'unibei land speech ((Jilmon) and 

 High Fnrness dialect ( 1'iketah = Barln-r) have 

 IIIMMI written by men who had lived only a few 

 years in the country, and hud IMJOII attracted by 

 the curious forms of the speech among which they 

 came. Others seem to have l*>en written purely 

 'from the fun of the tiling,' such as the Essex 

 'Tiptree Fair' and 'John Noakes and Mary Stiles,' 

 and the Kent 'Dick and Sal.' One of the few 

 modern books written with a desire to show the 

 better side of the dialect na di-t ingui-hfd from its 

 ludicrous side is the late Rev. W. Barnes's Dorset- 

 shire poems. There are also many serious Cumber- 

 land poems given by Gilpin. Nathan Hogg's 

 ( Baird s) poems and the Exmoor Scolding, as edited 

 by Elworthy, with the pronunciation and notes, 

 deserve study as the work of natives. The legion 

 of Lancashire and Yorkshire books is chiefly rol- 

 licking. But Tim, Bobbin has become a classic. 

 In Northumberland the Pitman's Pay takes a 

 similar position. Both have influenced the ortho- 



S-aphy used by other writers. In Scotland, besides 

 urns and Scott, must \*e mentioned the excellent 

 Aberdeenshire Johnny Gibb of Gushetneuk, and the 

 same writer's Life among my ain Folk. Dennison's 

 Orcadian Sketch Book is also first-rate. 



The Bibliofiraphieal List of works relating to dialects, 

 including both glossaries and examples, published by the 

 English Dialect Society, which was founded in 1873, 

 contains 200 pages ; and the Eivjlixh Dinlirt Dictionary 

 ( 1898 et scq. \ edited by Professor Joseph Wright, is based 

 on the Society's publications and collections. 



Dialectic is a Greek word which signified 

 originally 'the art of rational conversation,' but 

 came to have a technical signification in the lan- 

 guage of philosophy. At first it implied a regular 

 and scientific inetiind of treating general concep- 

 tions or general terms - a sort of anatomy of names, 

 and through them of the things denoted. In the 

 Socratic philosophy, and more especially in that of 

 Plato, dialectic was thus the method of the highest 

 and deepest kind of speculation. Aristotle gave 

 another signification to the word. According to 

 him, a scientific proof or deduction is different from 

 a dialectic proof, which is only a probable deduc- 

 tion. After this, dialectic came round to imply a 

 kind of fencing in words, the art of so using the 

 forms of reasoning as to confound your opponent, 

 and make fallacies pass for truth. Dialectic i- 

 sometimes used as synonymous with logic. The 

 Hegelian philosophy "regards dialectic as at once 

 the method of knowledge and of the evolution of 

 the universe itself. 



Di'allnge (Gr. dialing^, 'interchange;' so 

 called from its changeable colour), a mineral nearly 

 allied to Augite (q.v.), and by some regarded as a 

 variety of it. Its chemical comixmitiou is essen- 

 tially the same. It is seldom found perfectly 

 crystallised, but usually massive, -lauular, or dis- 

 seminated, and is characterised by its markedly 

 laminated structure. It is brown, gray, or green 

 in colour, but shows a kind of metallic lustre when 

 broken across the cleavage. This is due to the 

 presence of microscopic tubular inclusions or leaf- 

 lets, which are disposed parallel to the cleavage- 

 planes or lamina;. Diallage is a rock-forming 

 mineral of some im|>ortance, occurring as a primary 

 constituent of Gabbro (q.v.). 



Dialogue, a conversation between two or more 

 persons, implying, however, greater unity and con- 

 tinuity of subject than an ordinary conversation. 

 The ancient Greek philosophers were fond of this 



: ...1,,1.,,-tiM- tin-it invwtlgftttnoa and eoavey- 

 ing tin -it in -ii i.. tioua, I lit- ftjcratic dialogue i* a 

 conversation in the form uf question and anawrr. *> 

 contrived that (be pi i-.n <|Uttionr<l I* led bliuaatf 

 t<> 1. 1 1 './in. it tli.iM* idvan that tin- questioner wiabea 

 to bring before him. The dialogue* of Pluto are, 

 as it were, philosophical drama*, in vthich tbe 

 Socratic method uf investigation i* brought to hear 

 upon speculative subject-. </,,- of tbe groateat 

 man tern in this form wan Lncian, win** keen-edged 

 and brilliant wit wan e^pecialls ttd;ipl<-d to it. The 

 dialogue is but ill adapt"! to the i-x jMt.it ion of 

 modern science, alt hough elementary blind lMik in 

 the form of question and an- vr an- -till uneful M 

 supplying the student with a series of concrete fact* 

 tersely expressed. Of the more em incut modern 

 writers of the literary forms of dialogue, we may 

 mention Erasmus in Latin ; Letting, Herder, and 

 NVieland among the Hermans; Petrarch and 

 Muchiavelli in Italy; Fenelon, Fontenelle, and 

 Diderot in France; and in England, lU-rk* 

 Swift, Muni, Harris, Helps, and Landor in his 

 linmj, iinni t'oni'craationt. Dialogue combined with 

 !>.. lion gives us the drama. 



Dialysis. See OSMOSE, DIFFUSION. 



DiainatflK'tisin. Bodies sach as iron, when 

 placed in a field of magnetic force, tend to move 

 from places of weaker to places of stronger force. 

 The opposite is true of bismuth and other sub- 

 stances. Such substances are said to be diamag- 

 netic. For further information, see MAGNETISM. 



Diaiiiantiua, an episcopal town, of mean 

 appearance, in the Brazilian state of Minas 

 (ier.tes. It i- the centre of a rich diamond di-trict, 

 and has manufactures of cotton and gold ware. 

 Pop. 13,000. 



Diameter* in Plane Geometry, is generally a 

 straight line bisecting any system of parallel chords 

 of a conic section. The lines which it bisects are 

 termed its ordinatet. In the circle, ellipse, and 

 hyperbola, every diameter passes through the centre 

 of the curve, and is there bisected ; but it is only 

 in the cane of the circle that all diameters are 

 equal. In the parabola, since the centre of the 

 curve is at an infinite distance, all diameters are 

 parallel to the axis. 



Diamond (corrupted from adamant, q.v.), a 

 natural form of crystallised carlion, highly valued 

 as a precious stone, but of much le-s value than the 

 ruby. The diamond crystallises in the cubic or 

 monometric system, its common forms being the 

 regular octahedron, the rhombic dodecahedron, and 

 the six-faced octahedron. The faces are < 

 curved, and the general form of the crystal is more 

 or less rounded. Cleavage is perfect, parallel to 

 the faces of the octahedron a fact which is often 

 taken advantage of in si. lilting otf frngineir 

 the purpose of removing tlaws. The urla>e of the 

 diamond frequently exhibits stria- and triangular 

 impression?., while 'the interior may contain n. 

 scopic cavities and various inclu-ioiiH. A distinctly 

 lamellar structure is bv no mean- uncommon. 



The lu-tre of tbe diamond i peculiar to itself, 

 and hence termed 'adamantine.' In a natural con- 

 dition, however, the surface often presents a dull 

 lead gray semi metallic lu-tn-. The high refractive 

 and disJM-r-ive |xiwei of the diamond produce, 

 when the -tone is jndici-M.sK cut. a brilliancy and 

 ' fire ' unequalled by anv other stone. The mean 

 index of refraction" is 'j'4, and the angle of total 

 reflection about -J4 "24 : the latu-r account* for the 

 lu-tre. ina-much as a large proportion f the inci- 

 dent light is in a well cut diamond reflected from 

 the inner snrface of the stone. The diamond, 

 especially when coloured, is highly ph<*] 

 that is to say, after exposure to brilliant illumina- 

 tion it emits the rays which it has absorbed, and 



