DIP 



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DIR 



at courts are hence termed a diplomatic 

 tody, and severally, diplomatists. At the 

 Congress assembled at Vienna, 1814, it 

 was arranged that the rank of diplomatic 

 agents should be: 1. Ambassadors; 2. 

 Envoys Extraordinary and Ministers Ple- 

 nipotentiary ; 3. Ministers resident; 4. 

 Charge's d' Affaires ; 5. Secretaries of Le- 

 gation and Attache's. 



DIPLOMATICS, the science of diplomas or 

 ancient writings, literary and public do- 

 cuments, decrees, charters, and having 

 for its object the deciphering of old 

 writings, and the discussing of their au- 

 thenticity, dates, &c. 



DIP'LOPY, Lat. diplopia, a disease of the 

 eye in which the person sees an object 

 double, from livKaos, double, and 

 oxTOftKi, to see; the visits duplicatus. 

 The cause of the affection is not well 

 known. 



DIPLO'ZOON, from StxXoo?, double, and 

 &6, an animal; i.e. double animal, a 

 very singular worm which infests the 

 gills of the bream, having two distinct 

 bodies united in the middle, resembling 

 a St. Andrew's cross. 



DIPPING (see DIP). Among miners, the 

 interruption of a vein of ore. In magnet- 

 ism, the depression of the pole of a mag- 

 net or magnetic needle is called its dip, 

 and the amount is shown by the dipping- 



needle. This needle, A B, is a flat mag- 

 net, through the centre of which a small 

 axis passes at right angles. It moves 

 freely in circular holes made in the hori- 

 zontal bar, C D, which forms the diame- 

 ter of a circle, graduated for the purpose 

 of showing the angle which the needle 

 makes with the horizon. At the equator 

 the needle takes the horizontal position, 

 from which position it deviates in pro- 

 portion as it is approached towards either 

 pole : this may be shown by using a large 

 artificial magnet. 



DIP'TERA, an order of insects character- 

 ised by having two nu'mbranniK. ex- 

 tended wings, whence the name from 



and TTi^nt, a wing. The epithet fof 

 this order is dipterous or dipteral. 



DIPTERA'CI:.*:, a natural order of arbo- 

 rescent exogens. 



DIP'TERON, from ^nrrt^ef, two-winged ; 

 the name given by the old architects to 

 an edifice with a double row of columns, 

 which formed porticoes called wings or 

 aisles. 



DIPTERT'OIANS, ^rrr^y^, two-finned ; a 

 family of fishes having only two fins. 



DIP'TYCH (Gr.), twofold, a. tablet used by 

 the Romans for the purpose of writing, 

 and folded like a book of two leaves. 

 "NVhen it consisted of several leaves it was 

 called polyptych. The tablet was formed 

 of wood or some metallic substance. 



DI'PUS, the generic name given by 

 Gmelin to the Jerboas belonging to the 

 rat-tribe. The jerboa is found from Bar- 

 bary to the north of the Caspian Sea, is 

 the size of a rat, lives in burrows, and 

 becomes torpid during winter. Dipus 

 means two-footed, and the common jerboa 

 (D. sagitta) is often called the two-footed 

 mouse (a name more or less applicable to 

 all the species) ; from the great length of 

 its hind-legs and the shortness of its fore- 

 paws, its motions resemble those of a 

 bird. 



DIP'YRE, amineral of the zeolite family, 

 thus named from $tf and &vg, fire, be- 

 cause it melts and phosphorises at the 

 same time before the blow-pipe. It is a 

 silicate of alumina and lime. 



DIRECT', from directus, straight. In 

 astronomy, a planet moves direct when 

 its motion is forward in the zodiac or in 

 the direction of the signs (see CONSEQUEN- 

 Ti.O : opposed of retrograde. In music, an 

 interval is direct when it forms harmony 

 on the fundamental sound which produces 

 it ; and a direct is a character placed at 

 the end of a stave to direct the performer 

 to the first note of the next stave. In 

 arithmetic. See PROPORTION and RATIO. 

 In geometry. See RIGHT. In optics. See 

 RAY. A direct dial is one which points 

 directly to one of the four cardinal points. 

 A direct tax is one upon real estate and 

 houses and lands. 



DIRECTION. In mechanics, (1.) The line 

 of direction is the. line in which a body 

 moves, or in which force is applied ; (2.) 

 The angle of direction is that included 

 between the lines of direction of two 

 conspiring forces; (3.) The quantity of 

 direction has the same meaning as mo- 

 mentum. 



DIREC'TOR. 1. A person appointed to 

 manage the affairs of a public company. 



2. A grooved instrument or probe for 



guiding the knife in some surgical opera- 

 tions. 3. The name of a muscle. 



DIREC'TRIX. In mathematics, (1.) A 

 line drawn perpendicular to the axis at 



