DBF 



DEG 



whereas in the quality of King, de Roy, 

 the articles of andcfe mark nothing pre- 

 cise, and are therefore indefinite. 



DEFINITION, the shewing the mean- 

 ing of one word by several other not sy- 

 nonymous terms. The meaning of words 

 being only the ideas they are made to 

 stand for by him that uses them, the 

 meaning of any term is then shewed, or 

 the word is defined, when by other words 

 the idea it is made the sign of, and is an- 

 nexed to it in the mind of the speaker, 

 is, as it were, represented and set before 

 the view of another ; and thus its signifi- 

 cation is ascertained. This is the only 

 end and use of definitions, and therefore 

 the only measure of what is, or is not, a 

 good definition. 



The names then of simple ideas are 

 ihcapable of being defined, because the 

 several terms of a definition signifying se- 

 veral ideas, they can altogether by no 

 means represent an idea which has no 

 composition at all ; and therefore a defi- 

 nition, which is properly but shewing the 

 meaning of any one word by several others, 

 not signifying the same each, can in the 

 names of simple ideas have no place. 

 Definitions which then take place in com- 

 pound ideas only are of two sorts : the 

 definition of the name, which is the ex- 

 planation of what any word means ; and 

 the definition of the thing, which explains 

 in what the nature of that thing consists. 



The special rules for a good definition 

 are these : 1. A definition must be uni- 

 versal, or adequate, that is, it must agree 

 to all the particular species, or individu- 

 als, that are included under the same 

 idea. 2. It must be proper, and peculiar 

 to the thing defined, and agree to that 

 alone. These two rules being observed, 

 will always render a definition reciprocal 

 with the thing defined, that is, the defi- 

 nition may be used in the place of the 

 thing defined ; or they may be mutually 

 affirmed concerning each other. 3. A 

 definition should be clear and plain ; and 

 indeed it is a general rule concerning the 

 definition both of names and things, that 

 no word should be used in either of them, 

 which has any difficulty in it, unless it 

 has been before defined. 4. A defini- 

 tion should be short, so that it must have 

 no tautology in it, nor any words super- 

 fluous. 5. Neither the thing defined, nor 

 a mere synonymous name, should make 

 any part of the definition. 



DEFLAGRATION, in chemistry, the 

 act of burning two or more substances to- 

 gether, as charcoal and nitre. When a 

 quantity of nitre, (nitrate of potash,) is 

 3rixed with an equal weight of sulphur, 



charcoal, or other inflammable substance, 

 if the mixture is thrown into a crucible 

 heated to redness, a very vivid combus- 

 tion is instantly excited : this is deflagra- 

 tion, \vhich is thus explained : nitre is a 

 compound of nitric acid and potash : ni- 

 tric acid consists of nitrogen and oxygen ; 

 the nitre, therefore, contains a large por- 

 tion of oxygen, which is in so weak a 

 state of combination, that it is separated 

 by exposure to a red heat. When, there- 

 fore, the mixture of the nitre and of the 

 inflammable body is thrown into the 

 heated crucible, the oxygen of the for- 

 mer is disengaged; it is thus suddenly 

 presented to the inflammable body, and 

 hence the vivid combustion that is excit- 

 ed ; and for the production of this, it is 

 not even requisite to raise the tempera- 

 ture so high as that which would be ne- 

 cessary, if applied alone, to decompose 

 the nitre, the affinity of the inflammable 

 body to the oxygen of the nitre causing 

 it to take place at a temperature some- 

 what lower. The nitrogen, or azote of 

 the nitric acid, passes oft in the state of 

 gas/ and the potash with which the acid 

 was united remains mixed, or united with 

 the body formed by the combination of 

 the oxygen, and the inflammable sub- 

 stance. 



DEFORMITY, the want of that unifor- 

 mity necessary to constitute the beauty of 

 an object. See BEAUT*-. 



DEGLUTITION, in medicine, the act 

 of swallowing the food, performed by 

 means of the tongue driving the aliment 

 into the oesophagus, which, by the con- 

 traction of the sphincter, protrudes the 

 contents downwards. 



DEGRADATION, a punishment of de- 

 linquent ecclesiastics. The canon law dis- 

 tinguishes it into two sorts ; the one sum- 

 mary, by words only ; the other solemn, 

 by stripping the person degraded of those 

 ornaments and rights which are the en- 

 signs of his order or degree. 



DEGRADED cross, in heraldry, a cross 

 divided into steps at each end, diminish- 

 ing as they ascend towards the centre, 

 called by the French perronnce. 



DEGREE, in geometry, a division of 

 circle, including a three hundred and su 

 tieth part of its circumference. Evei 

 circle is supposed to be divided into 

 three hundred and sixty parts, called de- 

 grees, and each degree divided into sixty 

 other parts, called minutes ; each of tin 

 minutes being again divided into si: 

 seconds, each second into thirds, at 

 each third into fourths, and so on. Bj 

 this means no more degrees or parts are 

 reckoned in the greatest circle than in 



