DECIUS MUS DECRESCENDO. 



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the attempt again. When the vowels are found, they 

 must, 3. be distinguished from each other. For 

 this purpose, it should be determined which vowel 

 occurs most frequently in the language in which 

 the manuscript is supposed to be written. In every 

 language, particular rules for determining the 

 vowels may be laid down. All the ordinary 

 modes of deciphering fail in the case of those 

 secret writings in which dictionaries are used as 

 the basis, and whole words, and even short sen- 

 tences, are denoted by single ciphers, and where, 

 also, the order of the ciphers, 1, 2, 3, &c., does 

 not correspond to the alphabetical arrangement 

 of the words in the dictionary, but is made as 

 irregular as possible, and non-valeurs, as they are 

 called, are made use of; that is, ciphers without sig- 

 nification, which are intermixed with the valeurs, or 

 those ciphers which supply the place of words. The 

 old modes of secret writing have been almost entirely 

 superseded, and the old modes of deciphering have 

 been made almost entirely useless by the modern 

 species of cryptography, in which, according to a 

 simple rule, which may be communicated verbally 

 and retained in memory, the signs for the letters may 

 be continually changed. This is the chiffre guarre, 

 or chiffre indechiffrable, used, if not universally, yet 

 by most courts. See Cryptography. 



DECIUS MUS, PUBLIDS; a Roman consul, who, 

 in a war against the Latins, B. C. 340, devoted him- 

 self to death for his country. His example was fol- 

 lowed by his son and his grandson. Such acts of 

 self-devotion (devotiones) were not unusual at that 

 time, when patriotism and piety exerted a powerful 

 influence, and were performed with great solemnity. 

 He who devoted himself, after performing certain 

 religious rites, rushed into the midst of the enemy, 

 clothed in splendid armour, to show his countrymen 

 how a brave man ought to die for his country. 



Decius was also the same of a Roman emperor, 

 who reigned from A. D. 249, till December 251. He 

 persecuted the Christians, and perished with his 

 army, in a bloody battle in Moesia against the Goths. 



DECK. See Ship. 



DECKER relates to the rate of a ship of force ; as 

 a two-decker, a three-decker; i. e. carrying two 

 entire tiers or ranges of cannon, or three such tiers. 



DECKER, or DEKKER, THOMAS, an English dra- 

 matic and miscellaneous writer, who lived in the 

 reigns of Elizabeth and James I. Nothing is known 

 of his personal history, except that he was one of the 

 literary antagonists of Ben Jonson, who had satir- 

 ized Decker in his Poetaster, and the latter had 

 taken his revenge in his Satyromastix. Some of 

 his plays have great merit, particularly his Honest 

 Whore, and his comedy of Old Fortunatus. All 

 his tracts are highly valued by bibliomaniacs. 



DECLINATION OF THE SUN, OF A STAR, 

 OR A PLANET, is its distance from the equinoctial, 

 northward or southward. When the sun is in the 

 equinoctial, he has no declination, and enlightens 

 half the globe from pole to pole. As he increases in 

 north declination, he gradually shines farther over 

 the north pole, and leaves the south pole in dark- 

 ness. In a similar manner, when he has south de- 

 clination, he shines over the south pole, and leaves 

 the north pole in darkness. 23 28' is the sun's 

 greatest declination north or south. 



DECOMPOSITION, CHEMICAL, is the resolution 

 of a compound substance into its constituent parts, 

 which are exhibited either separate, or in some new 

 combination. The compounds which are spontane- 

 ously formed by organic bodies, both vegetable and 

 animal, are of a different nature from those which 

 exist in unorganized matter. They are the peculiar 

 results of vital processes, and neither their structure 



nor composition can be imitated by art. During life 

 the elements of organic bodies are held together by 

 vital affinities, under the influence of which they 

 were originally combined. But no sooner does life 

 cease, than these elements become subject to the 

 laws of inert matter. The original affinities, which 

 had been modified or suspended during life, are 

 brought into operation ; the elementary atoms react 

 upon each other, new combinations are formed, and 

 the organized structure passes, sooner or later, into 

 decay. The rapidity with which decomposition takes 

 place in organic bodies depends upon the nature or 

 the particular substance, and upon the circumstances 

 under which it is placed. Temperature, moisture, 

 and the presence of decomposing agents, greatly 

 affect both the period and extent o? this process. By 

 regulating or preventing the operation of these 

 causes, the duration of most substances may be pro- 

 longed, and many materials are rendered useful, 

 which, if left to themselves, would be perishable and 

 worthless. The preservation of timber, of fibrous 

 substances, of leather, of food, and of various objects 

 of art, is a subject of the highest importance, and has 

 received, at various times, much attention from scien- 

 tific experimentalists. 



DECOY, among fowlers ; a place made for catch- 

 ing wild-fowl. A decoy is generally made where 

 there is a large pond surrounded witli wood, and be- 

 yond that a marshy and uncultivated country. If the 

 piece of water is not thus surrounded, it will be sub- 

 jected to noises and other accidents, which may be 

 expected to frighten the wild-fowl from the haunt, 

 where they would otherwise sleep in the day-time. 

 If these noises or disturbances are wilful, it has been 

 held that an action will lie against the disturber. As 

 soon as the evening sets in, the decoy-birds rise, as 

 the wild-fowl feed during the night. If the evening 

 is still, the noise of their wings, during their flight, is 

 heard at a very great distance, and is a pleasing, 

 though rather melancholy sound. 



Decoy, in military affairs ; a stratagem to lure the 

 enemy into an ambush, &c. 



DECREE, in general ; an order, edict, or law made 

 by a superior, as a rule to govern inferiors. It is 

 used for a judicial decision in the court of chancery; 

 also for the edicts of ecclesiastical councils. In the 

 civil law, it signified a determination or judgment of 

 the emperor on a suit between parties. The com- 

 pilation of the older papal decretals and the decrees 

 of the councils, made by the monk Gratianus in the 

 eleventh century, is called the Decretum Gratiani. 

 (See Canon Law.) In the former German empire, 

 the resolutions of the emperor, declared to the estates 

 of the empire, were called decrees. The old name of 

 royal arders, in France, was ordonnances or lettres. 

 The national convention, while it possessed t-overeign 

 power, used the expression La convention nationals 

 deer etc. During the period of the directory, and 

 under the consular government, the expressions 

 arret and arreter were customary ; but the impe- 

 rial government used the words imperial decree, 

 for instance, in the famous decrees of Berlin and of 

 Milan. 



DECREPITATION is the crackling noise, accom- 

 panied by a violent exfoliation of their particles, 

 which is made by several salts and earthy com 

 pounds, on being suddenly exposed to heat. It ap- 

 pears to be referable to the same cause which occa- 

 sions the cracking of glass and cast-iron vessels, 

 when they are incautiously heated ; viz., the unequal 

 expansion of the lamina which compose them, in 

 consequence of their imperfect power of conducting 

 heat. 



DECRESCENDO; an Italian term in music 

 which denotes the gradual weakening of the sound. 



