P A P P A P on numerous and varied investigations, in the course of which he discovered a siphon acting in the same manner as the "Sipho Wirtembergicus " (Phil, Tr., 1685), and also constructed a model of an engine for raising water from a river by means of pumps worked by a water-wheel driven by the current. In November 1687 he was ap pointed to the chair of mathematics in the university of Marburg, and here he remained until 1696, when he re moved to Cassel. From the time of his settlement in Germany he carried on an active correspondence with Huygens and Leibnitz, which is still preserved, and in one of his letters to Leibnitz, in 1698, he mentions that he is engaged on a machine for raising water to a great height by the force of fire ; in a later communication he speaks also of a little carriage he had constructed to be propelled by this force. Again in 1702 he wrote about a steam " ballista," which he anticipated would "promptly compel France to make an enduring peace." In 1705 Leibnitz sent Papin a sketch of Savery s engine for raising water, and this stimulated him to further exertions, which re sulted two years afterwards in the publication of the Ars nova ad aquam ignis adminiculo efficacissime elevandam (Cassel, 1707), in which his high-pressure boiler and its applications are described (see STEAM-ENGINE). In 1707 he resolved to quit Cassel for London, and on September 24th of that year he sailed with his family from Cassel in an ingeniously constructed boat, propelled by paddle- wheels, to be worked by the crew, with which he appa rently expected to reach the mouth of the Weser. The expedition, however, came to an ignominious end at Miinden, where the vessel was confiscated at the instance of the boatmen, who objected to the invasion of their ex clusive privileges in the Weser navigation. Papin, on his subsequent arrival in London, found himself without re sources and almost without friends ; various applications through Sloane to the Royal Society for grants of money were made in vain, and he died in total obscurity, pro bably about the beginning of 1712. The published writings of Papin, besides those already referred to, consist for the most part of a large number of papers, princi pally on hydraulics and pneumatics, contributed to the Journal des Savans, the Nouvellcs do la licpubliqiie des Lettres, The Philosophical Transactions, and the Ada Ermlitorum ; many of them were collected by himself into a Fasciculus dissertationum (Marburg, 1695), of which he published also a translation into Frencn (Rccueil cL divcrscs pieces toiichant quclques nouvelles machines (Cassel, 1695). His correspondence with Leibnitz and Huygens, along with a biography, has been published by Dr Ernst Gerland (Leibnizeris und Huyycns Briefwechsel mil Papin, nebst der Biographic Papin s, Berlin, 1881). PAPINIAN, the most celebrated of Roman jurists, was mar/ister libellorum and afterwards praetorian prefect under Septimius Severus. He was an intimate friend of the emperor, whom he accompanied to Britain, and before his death Severus specially commended his two sons to his charge. Papinian was faithful to his trust, and tried to keep peace between the brothers, but with no better result than to excite the hatred of Caracalla, to which he fell a victim in the general slaughter of Geta s friends which followed the fratricide of 212 A.D. The details are variously related, and have undergone legendary embellishment, but it is certain that the murder of Papinian, which took place under Caracalla s own eyes, was one of the most disgraceful crimes of that hideous tyrant. Little more is known about Papinian. He was perhaps a Syrian by birth, for he is said to have been a kinsman of Severus s second wife, Julia Domna ; that he studied law along with Severus under Scsevola is asserted in an interpolated passage in Spartian (Caracal., c. 8). Papinian s place and work as a jurist will fall to be dis cussed under ROMAN LAW (<j.v.}. PAPPENHEIM, GOTTFRIED HEINRICH, GRAF zu (1594-1632), imperialist general in the Thirty Years War, was born on the 29th May 1594. He attended the high schools of Altdorf and Tubingen, but did not seem to profit much by the instruction he received at either institution. In his twentieth year he joined the Roman Catholic Church ; and zeal for his new faith induced him to enter the military service of King Sigismund in Poland and afterwards that of Maximilian, duke of Bavaria, head of the Catholic League. In 1620, as a colonel in the army of the League, he distinguished himself in the battle near Prague which decided the fate of Frederick, king of Bohemia. In this battle, after fighting with extraordinary energy, he was severely wounded, and for many hours lay unnoticed under his horse. He received, in 1623, the command of a regiment of cuirassiers who became famous as the Pappenheimer, and with them he fought from 1623 to 1625 at the head of the Spaniards in Lombardy. In 1626, having been recalled to Germany by Duke Maximilian, he crushed an insurrection of peasants in Upper Austria, obtaining in the course of a month a series of victories in which 40,000 peasants are said to have been killed. He then went to the help of Tilly against Christian IV. of Denmark, and took a prominent part in the storming of Magdeburg, the inhabitants of which were treated by him and by his soldiers with savage cruelty. After the battle of Breitenfeld, which was fought at an unsuitable time, contrary to the wish of Tilly, in conse quence of Pappenheim s impetuosity, he covered the retreat of the imperialists ; and in Westphalia and the country of the lower Rhine he stimulated the enthusiasm of his party by several successful engagements. When Tilly died, Pappenheim aided Wallenstein in subduing Saxony. On his way to the lower Rhine, where he proposed to support the Spaniards, he was summoned by Wallenstein to Liitzen, where battle was about to be given to Gustavus Adolphus ; and at the moment of his arrival fortune seemed already to have declared for the Swedes. Pappenheim threw himself into the conflict, and his attack was so furious that the enemy began to give way ; but two musket balls penetrated his breast, and he had to be carried from the field. He died on the 17th November 1632, the day after the battle. He left behind him the reputa tion of one of the bravest warriors and most ardent Catholics of his day. Notwithstanding the sternness of his discipline, he was idolized by his troops. See Hess, Gottfried Heinrich, Graf zu Pappenheim, 1855. PAPPUS, OF ALEXANDRIA, a geometer of a very high order, belongs to a time when already the Greek mathematicians of great original genius had been succeeded and replaced by a race of learned compilers and com mentators, who confined their investigations within the limits previously attained, without adding anything to the development of mathematics. To the general medio crity Pappus must be considered to be a remarkable exception ; for, although much even of his work is of the nature of compilation (which is, however, itself of great historical value), there is yet much the discovery of which cannot well be attributed to any one else. According to Proclus, he was at the head of a school ; but how far he was above his contemporaries, how little appreciated or understood by them, is shown by the absence of references to him in other Greek writers, and by the fact that his work had no effect in arresting the decay of mathematical science. In this respect the fate of Pappus strikingly resembles that of Diophantus, another living power amid general stagnation. In reading the Collection of Pappus, we meet with no indication of the date of the authors whose treatises he makes use of, or of the time at which he himself wrote. If we had no other information than can be derived from a perusal of his work, we should
