DIFFERENTIAL CALCULUS DIGESTION. 



677 



second army $ and, the value of his services being ap- 

 preciated, he was at length made a brigadier-general 

 of cavalry. The French troops sent against him were 

 almost uniformly defeated ; but, on one occasion, he 

 was overpowered, and only escaped falling into their 

 hands, by leaping down a dangerous precipice. 

 He attended the duke of Wellington in triumph to 

 Madrid, after the expulsion of the French, and, some 

 time after, received his commands to join the second 

 army in the neighbourhood of Tortosa, at the head of 

 4850 men, horse and foot. All the services of this 

 brave officer, during the war which preceded the 

 restoration of Ferdinand, could not atone for the 

 crime of opposing the invasion of the liberties of 

 Spain, after the return of that prince. The Empe- 

 cinado had laid down his arms on the faith ot a 

 treaty ; notwithstanding which, he was seized and 

 executed at Rueda, August 19, 1825, with circum- 

 stances of insulting cruelty highly disgraceful to his 

 persecutors. As the originator of that system of de- 

 sultory warfare which contributed much to the expul- 

 sion of the invading army from Spain, Diez has 

 strong claims to notice. His natural talents were 

 not assisted by education, as he could write no more 

 than his name ; his manners were rude, and his tem- 

 per violent ; yet he was partial to the society of well- 

 informed persons, and disposed to attend to their ad- 

 vice ; while, with the greatness of mind which char- 

 acterizes conscious worth, he never scrupled to 

 acknowledge his humble origin, or the limited sphere 

 of his information. 



DIFFERENTIAL CALCULUS. See Calculus. 



DIGAMMA, in the Greek language. In addition 

 to the smooth and rough breathings, the ancient Greek 

 language had another, which remained longest 

 among the ^Eolians. This is most commonly called, 

 from the appearance of the character used to denote 

 it, a digamma, that is, double r. It was a true con- 

 sonant, and appears to have had the force of/ or v. 

 It was attached to several words, which, in the more 

 familiar dialect, had the smooth or rough breathing. 

 The whole doctrine, however, of the digamma, for 

 want of literary monuments, remaining from the 

 period when it was most in use, is exceedingly 

 obscure. See Buttmann's Greek Grammar, from the 

 German, by Ed. Everett, 2d edit. Boston, 1826. 



DIG BY, SIR KENELM, the eldest son of the un- 

 fortunate Sir Everard Digby, was born at Gothurst, in 

 Buckinghamshire, in 1603. He was educated in the 

 Protestant religion, and entered at Gloucester hall, 

 Oxford. On his return from his travels, he brought 

 back with him a recipe for making a sympathetic 

 powder for the cure of wounds, being much addicted 

 to the philosophy which employed itself in alchymy 

 and occult qualities. On the accession of Charles I., 

 he was created a gentleman of the bed-chamber, a 

 commissioner of the navy, and a governor of the 

 Trinity house. He soon after fitted out a small 

 squadron at his own expense, to cruise against the 

 Algerines and Venetians, and obtained some advan- 

 tages over the shipping of both these powers. He 

 returned with a great increase of reputation, and, 

 having a good address and a graceful elocution, with 

 a fine person and an imposing manner, he made a 

 considerable figure. On a visit to France, he was 

 converted to the Catholic religion. On the breaking 

 out of the civil war, he was committed prisoner to 

 Winchester house, where he amused himself by 

 writing observations on the Religio Medici of Sir 

 Thomas Browne, and on the ninth canto of the 

 Fairy Queen, in which Spenser has introduced some 

 mysterious matter in regard to numbers. Being 

 liberated, he passed into France, and visited Descar- 

 tes. In 1646, he printed at Paris his own philosophi- 

 cal system, in two works, entitled a Treatise on the 



Nature of Bodies, and a Treatise on the Nature and 

 Operation of the Soul. In 1651, he also published 

 Institutionum Peripateticarum, cum Appendice theolo- 

 gica de Origine Mundi. All these treatises are written 

 in the spirit of the corpuscular philosophy, which 

 they support with more learning and ingenuity than 

 solidity or force. After the ruin of the royal cause, 

 he returned to England to compound for his estate, 

 but was not allowed to remain. He resided in the 

 south of France in 1656 and 1657, and produced at 

 Montpellier, a Discourse on the Cure of Wounds by 

 Sympathy. On the restoration, he returned to Eng- 

 land, became a member of the royal society, and was 

 much visited by men of science. He married a Jady 

 who was highly distinguished for beauty, and. in 

 other respects, almost as singular as himself. Of tliis 

 lady, Venetia Digby, a great many pictures and busts 

 are extant ; but she died while still young. Sir Ken- 

 elm died in 1665, at the age of sixty-two. 



DIGBY, LORD GEORGE, son of John, earl of Bris- 

 tol, was born during his father's embassy to Ma- 

 drid in 1612. He distinguished himself much while 

 at Magdalen college, Oxford, and, in the beginning 

 of the long parliament, opposed the court, but se- 

 ceded from the opposition, on the measures against 

 the earl of Strafford. He then distinguished himself 

 as warmly on the side of the king, and was made 

 secretary of state in 1643. After the death of 

 Charles, he was excepted from pardon by the parlia- 

 ment, and was obliged to live in exile until the re- 

 storation, when he was made knight of the garter. 

 He wrote a comedy called Elvira, and also letters to 

 his cousin, Sir Kenelm Digby, against popery, al- 

 though he ended by becoming a Catholic himself. 



DIGEST. See Civil Law. 



DIGESTER ; an instrument invented by Mr Pa- 

 pin. It consists of a strong vessel of copper or iron, 

 with a cover adapted to screw on, with pieces of felt or 

 pasteboard interposed. A valve with a small aperture 

 is made in the cover, the stopper of which valve 

 may be more or less loaded, either by actual weights, 

 or by pressure from an apparatus on the principle of 

 the steelyard. The purpose of this instrument is to 

 prevent the loss of heat by evaporation. Water 

 may be thus heated to 400 Fahr. ; at which tempera- 

 ture its solvent power is greatly increased. 



DIGESTION is that process in the animal body, 

 by which the aliments are dissolved, and the nutri- 

 tive parts are separated from those which cannot af- 

 ford nourishment to the body. The organs effecting 

 this process are divided into the digestive organs, pro- 

 perly so called, and the auxiliary organs. The for- 

 mer are composed of the divisions of the intestinal 

 canal, which includes the stomach, the great and 

 small intestines, &c. To the latter belong the liver, 

 the pancreas, and the spleen. The first process of 

 digestion is the solution of the aliments. When the 

 aliments, after being properly prepared, and mixed 

 with saliva by mastication, have reached the stomach, 

 they are ultimately united with a liquid substance 

 called the gastric juice, by the motion of the stomach. 

 By this motion, the aliments are mechanically separ- 

 ated into their smallest parts, penetrated by the gas- 

 tric juice, and transformed into a uniform pulpy or 

 fluid mass. At the same time, a solution of the ali- 

 ments into their simple elements, and a mixture of 

 them so as to form other products, takes place, effec- 

 ted partly by the peculiar power of the stomach and 

 the liquid generated in it, partly by the warmth of 

 this organ. This pulpy mass, called chyme (q. v.), 

 proceeds from the stomach, through the pylorus, into 

 the part of the intestinal canal called the large intes- 

 tines (q. v.), where it is mixed with the pancreatic 

 juice and the bile. (See Bile, and Pancreas.) Both 

 these liquids operate most powerfully on the cfayine. 



