473 



DEPARTURE. 



DERVISH. 



474 



ments, cantons, and communes. They will be found described under 

 FRANCE, and each department by name, in the GEOG. Div. 



DEPARTURE, a nautical term used to indicate the number of 

 miles which a ship has sailed eastward or westward ; and it always has 

 reference to a certain meridian which the ship was upon, when her 

 previous position had been calculated. 



When a ship sails on any course but true north or south, she leaves 

 or " departs " from her meridian : hence the word. 



From the obliquity of the course in such cases, when not sailing due 

 east or west, a triangle is formed, of which in " dead reckoning " the 

 base is assumed to be the "departure," the perpendicular being the 

 difference of latitude, and the hypothenuse the distance. In its most 

 simple form, that of plane sailing, the earth's surface is for convenience 

 supposed to be flat ; hence the term departure can only be applicable 

 to short distances, such as a day's run. 



The difference between departure and longitude may be thus illus- 

 trated : If we construct a right-angled triangle, of which the base 

 contains the number of given miles of declination, and make the acute 

 angle at the base equal to the given latitude, the hypothenuse will 

 measure the corresponding geographical miles of longitude, or, by 

 logarithms, Cos. Lat. : Dep. : : Rad. : Diff. Long. 



Dep. x Rad. 



'. Din. Lone =-7; f r and 



6 Cos. Lat. 



Dep. = 



Cos. Lat. x Diff. Long. 

 Radius. 



Taking a departure is the ascertaining of the ship's position with 

 regard to some prominent headland which is in sight at the time of 

 commencing what is called a sea log, and it fixes the starting-point for 

 the voyage. This is generally done by one of three methods, namely : 



1. Either a single bearing [BEARING] is taken of some known object 

 on shore, and its distance estimated ; or, 



2. A bearing is first taken of one object, and after sailing a measured 

 distance on a known compass course, a second bearing is taken of the 

 game object, and the required side of a triangle thus found is measured 

 or computed ; or, 



3. Two land objects being in sight, the bearing of each is taken at 

 the same moment in the ship, and from these bearings laid off as re- 

 versed upon the chart the exact distance is at once measured : that 

 between the two objects on the chart forming the base line of the 

 triangle. 



In estimating at sea distances from high land in sight, so much 

 depends on the state of the atmosphere [REFRACTION] that even a 

 practised eye is liable to considerable error ; so that a second or cross 

 bearing, if obtainable, is always to be preferred. 



The position of a ship from the land on taking a departure, is usually 

 considered as if the first course in the traverse. [SAILINGS ; NAVIGA- 

 TION ; LONGITUDE.] 



DEPARTURE. [PLEADING.] 



DEPHLOQISTICATED. A term used by the chemists of the last 

 century to denote bodies which had been burnt ; or, according to the 

 then prevailing theory, deprived of their phlogiston. [CHEMISTRY, 

 Qtnrije Earnest Staid.} 



DKl'HLOQISTICATED MARINE ACID. [CHLORINE.] 



DEPLOY, to extend in a line of small depth, an army, a division, or 

 a battalion, which has been previously formed in one or more columns. 



DEPORTATION. [BANISHMENT.] 



DEPOSIT. This term is applied to the sum of money which, under 

 43 Geo. III. c. 46, a man may deposit with the sheriff after he is 

 arrested, instead of putting in special bail. [ Ai; i< I..ST. ] 



Deposit is also used for any sum of money which a man puts in the 

 bands of another as a kind of security for the fulfilment of some agree- 

 ment, or as a part payment in advance. 



The Roman word depotitum signified anything which a man put in 

 the hands of another to keep till it was asked back, without anything 

 being given to the depositarius for his trouble. The depositor was 

 - called deponens or depositor. The depositary was bound to take care 

 of the thing, and to make good any damage that happened to it through 

 fraudulent design (dotm) or gross neglect (lala culpa). The depositor 

 could recover the thing by action ; but the depositary was entitled to 

 satisfaction for any loss that he sustained in the matter of the deposit 

 by any default (culpa) on the part of the depositor. The depositary 

 ' could make no use of the deposit, except with the permission of the 

 depositor, either given in express words or arising from implication 

 If a man refused to return a deposit, and was condemned in an actioi 

 of deposit (actio depoiiti), infamy (infamia) was a consequence of the 

 condemnation. 



I Dig.' 18, tit. 3 ; Juvenal, ' Sat.' xiii. 60.) 



DEPOSITION in its extended sense means the act of giving publi< 

 testimony, but as applicable to English law the word is used to signify 

 the testimony of a witness in a judicial proceeding reduced to writing 

 Informations upon oath and the evidence of witnesses before magistrate 

 and coroners are reduced into writing in the very words used b; 

 the*witnesses, or as near as possible thereto. Evidence in the Court o 

 Chancery is now, under 15 & 16 Viet, c. 86, taken orally by examiner 

 who write down the evidence given in the form of a narrative, whicl 

 is read over to and signed by the witness. According to the ancien 



ractice, which may in some cases be still resorted to, evidence was taken 

 n written answers to interrogatories, which were in writing, either by 

 ommissioners appointed by the court for that purpose in the particular 

 ause, if the witness resided at a greater distance from London than 

 miles, or before the examiners of the Court of Chancery. The 

 ?ourt of Chancery has power to grant a commission for the examination 

 f witnesses residing abroad ; and by the 1 Will. IV., c. 22, extending 

 he provisions of the 13 Geo. III., c. 63, the courts of law at West- 

 minster, in actions pending before them, have power to order the exami- 

 lation of witnesses residing in any of her Majesty's foreign dominions. 

 A T hen a witness is above the age of seventy, or very infirm, or about to 

 go abroad, so that his testimony may be lost before the regular period 

 or his examination arrives, the Court of Chancery will order him to be 

 examined cle bene ewe, as it is termed ; that is, his examination is re- 

 ceived for the present, and will be accepted as evidence when the 

 aroper time for taking the other evidence in the cause arrives, if the 

 vitness cannot be then produced. Courts of law do not possess similar 

 >ower without the consent of both parties, but in order to enforce 

 consent they will put off the trial at the instance of a defendant, if the 

 ilaintiff will not consent : and if the defendant refuse, will not give 

 lim judgment in case of nonsuit. 



The Court of Chancery will also, upon bill filed by a person in the 

 ictual and undisturbed possession of property, and who has therefore no 

 iieans of making his title the subject of judicial investigation, but 

 which nevertheless may be materially affected by the evidence of living 

 witnesses, allow the witnesses to be examined in perpetiiam rei memoriam, 

 ;hat is, to perpetuate testimony. This is done in order that if any of 

 ;he witnesses should die before the title to the property is disputed, 

 their evidence may be preserved, otherwise a claimant might lie by 

 until all the evidence against him was lost. 



Depositions are not admitted as evidence in courts of law, unless the 

 witness is either dead, or, from some cause, beyond the control of tho 

 [>arty seeking to read the deposition, cannot be produced, or against 

 any other persons than the parties to the proceeding in which they 

 were taken, or claimants under them, and who had the opportunity of 

 cross-examining the witness. In cases, however, relating to a custom, 

 prescription, or pedigree, where mere reputation would be good evidence, 

 a deposition may be received as against a stranger. 



Depositions token in Chancery de bene esse before answer put in, 

 unless the defendant is in contempt for refusing to answer, are not 

 admissible as evidence in a court of law, because until the defendant 

 has answered he could not have an opportunity of cross-examining the 

 witness ; but the Court of Chancery will sometimes direct such depo- 

 sitions to be read. Such order, however, while it concludes the parties, 

 is not binding upon the court of law : of course, however, if the depo- 

 sitions be not read and the decision should be contrary to justice, the 

 Court of Chancery would interfere as between the parties. [EQUITY ; 

 EVIDENCE.] 



DEPRESSION (Algebra), the reduction of an equation to a lower 

 degree, by dividing both sides of it by a common factor. Thus 

 X s x 6 = having been found to have 2 as one of its roots is depressed 

 to an equation of the second degree by dividing by .r 2, which gives 

 .z* + 2x + 3 = : that is, the two roots of the latter equation are the 

 two remaining roots of the former. 



DEPRESSION, ANGLE OF, is the angle by which a line drawn 

 from the eye to any object dips below the horizon. [ELEVATION, 

 ANGLE OP.] 



DEPRESSION OF MERCURY. [BAROMETER.] 



DERIVATION. The term law of derivation almost explains itself. 

 Thus in finding the successive differential co-efficients of a power of x, 

 the law is, to get the next differential co-efficient, multiply the last by its 

 exponent, and reduce the exponent by a unit. To treat of derivation in 

 the most general sense would be to write a work on mathematical ana- 

 lysis, of which it may be said that most of its difficulties arise from 

 want of sufficient knowledge of methods of derivation. But there is a 

 more restricted use of the term, derived from the work of Arbogast, in 

 which it applies to those laws of derivation which spring out of Taylor's 

 Theorem. Hence the differential calculus, considered either in the 

 manner of Lagrange, or in that of Arbogast, is sometimes called the 

 calculus of derivations. Lagrange himself calls the differential co- 

 efficient a derived function, the objection to which is the application of 

 a generic term to one of its particular cases. For the successive 

 logarithms, sines, &c., differences, integrals, &c.,of a given function, are 

 also functions derived from the original in different ways. Neverthe- 

 less, the fundamental processes of the differential calculus have appro- 

 priated the word derivation ; but in this way : the derived function 

 nearly always means the differential coefficient, while the substantive 

 derivation is nearly always used in reference to the method of Arbogast. 



DERVISH is a Persian word, properly an adjective, which signifies 

 poor, indigent ; as a substantive it is used to denote a religious mendi- 

 cant, hermit, or any one who retires from social life in order to devote 

 himself entirely to religious contemplation. It is synonymous with 

 the Arabic Fakir, and both expressions are chiefly employed to 

 designate a class of persons in Mohammedan countries nearly corre- 

 sponding to the different orders of monks among the Christians. It 

 would be difficult to determine the age to which the origin of the 

 dervishes is to be referred. From time almost immemorial, pious men 

 in the East, as elsewhere, seem to have thought it meritorious to 



