Page:The American Cyclopædia (1879) Volume X.djvu/589

LOGIC LOGWOOD 583 sned by Copernicus, Kepler, Galileo, Newton, &c., rather than that which was taught as a theory by Bacon. Prof. Jevons illustrates his system of notation and his theories of deduc- tion by a wide range and most ample citation of examples. He discusses very elaborately the various methods of measurement and ob- servation, with cautions against the errors to which the student is liable ; and presents, on the whole, the most complete survey of the whole field of knowledge and inquiry that has yet been given to the public. In his psychol- ogy he is evidently a sensationalist, in that he does not believe either in any a priori element of knowledge or in any insight into the notion of things by which we can obtain necessary truths and axioms, which, while they may have been obtained on the occasion of an act of sense-perception, do nevertheless transcend the truths of sense-perception, and assert what can never be proved as absolute truths by any of the a posteriori processes, or by any pro- cesses that are based on sense-perception alone. Though thus a sensationalist in his psychology, Prof. Jevons is not, as one would naturally expect, a materialist in his ontology. He thinks that the modern doctrines of evolution, development, &c., as held by Spencer, Darwin, and those of their schools, are not only not proved, but cannot be proved on any premises within the sphere of knowledge, as distin- guished from mere conjecture and hypothesis, by the use of any of the methods or modes of reasoning known to logic or admissible within the domain of science. And even as a hy- pothesis designed to explain observed and known phenomena, he thinks that the system of the modern materialists, when attempting to explain the phenomena of the universe without the recognition of a personal creator, introduces more mysteries or insoluble prob- lems than it solves. In Germany, from the time of Hegel, logic has followed mostly in the direction he gave it (already described), " as," in the words of Ueberweg, " that part of phi- losophy which considers reason itself as the prius of nature and spirit." Among the wri- ters in this school may be mentioned, as most worthy of note, Kuno Fischer, Logik und Meta- physik (Heidelberg, 1852; 2d ed., 1865) ; Ha- nusch, ffandbuch der wissenschaftlichen Denk- lelire (Lemberg, 1843 ; 2d ed., Prague, 1850) ; Rosenkranz, WissenscJiaft der logisclien Idee (1858-'9; together with Epilegomena, 1862); and Karl Werder, Logik als Commentar und Erganzung zu Hegel's Wissenschaftslehre der Logik (Berlin, 1841). But as early as 1832 Beneke published his Lehrbuch der Logik als Kunstlehre, which was a protest in some sens^? against the direction Hegel had given to specu- lations under the name of logic, and was based upon a more practical view of the nature of the science. As a follower of Beneke we have Dressier, Die Grundleliren der PsycJiologie und Logik (Leipsic, 1867; 2d ed., 1870). We have also as specially worth noticing, and not in the Hegelian line, Trendelenburg's Elementa Logices AristoteUca (Berlin, 1836 ; 6th ed., 1868; with supplementary Erlauterungen, 2d ed., 1861), and Ueberweg's System der Logik und GescMcTite der logischen Lehren (Bonn, 1857; 3d ed., 1868). In 1872 Robert Grass- mann, a younger brother of the mathematician (see GRASSMANN), published Die Begriffslehre oder Logik, ziceites BucJi der Formenlehre oder Hathematik, in which he treats the whole science as a branch of mathematics. The sys- tem is analogous to that of Boole. The logical doctrines in regard to ideas, judgments, and inference are expressed in the form of defini- tions and equations between arbitrary sym- bols, and are treated like the theorems of alge- bra according to fixed rules of operation. LOGRONO. I. A province of Old Castile, Spain, bordering on Alava, Navarre, Saragossa, Soria, and Burgos; area, 1,945 sq. m. ; pop. in 1870, 182,941. The northern part is generally level and very fertile, producing large crops of grain, fruits, and vegetables, and pasturing great numbers of sheep, goats, cattle, mules, and horses. Superior wine and oil are manu- factured. The southern portion is crossed by the Sierra Neila, and consists mostly of bar- ren hills; but it is rich in iron, copper, tin, antimony, marble, and coal. Tlie province lies in the basin of the Ebro, which forms its northern boundary, and is traversed by several affluents of that river. It has limited manu- factures of linen, woollen, and cotton goods, pottery, cutlery, shoes, and hats. The most important towns, besides the capital, are Cala- horra and Arnedo. II. A city, capital of the province, on the Ebro, 153 m. N. N. E. of Madrid; pop. about 11,000. It is well built, with wide paved streets and fine squares, and is surrounded by a wall. It contains six churches, two hospitals, three convents, a Jesuit college, a prison, a theatre, and an orphan asylum, and is overlooked by the ruins of an ancient castle. There are manufactures of wine, oil, brandy, linen, woollen, and hempen fabrics, hats, leather, cards, and candles. The Ebro is here crossed by a magnificent bridge of 12 arches, built in 1138. The French cap- tured the town in 1808, and again in 1823. It was the headquarters of Gen. Espartero du- ring the closing period of the first Carlist war. LOGWOOD, a dyewood yielded by the log- wood tree (hamatoxylon Campechianum) of Central America. The tree belongs to the sub- order Ccesalpinea of the natural order legumi* noscB. It grows in very favorable situations 40 or 50 ft. high, but more commonly not more than 25 ft. Its trunk is generally less than 20 inches in diameter, and is crooked and covered with a rough bark. The branches are also crooked and furnished with thorns. The flow- ers, in axillary racemes, have a purplish calyx and light yellow petals. The outer sap wood is yellow, but the inner portion, which alone is exported, is deep red. It is a close-grained wood, very hard, and so heavy that it sinks in