HAETMANN perhaps the first attempt to explain psycholo- gical phenomena on physiological principles. According to him, the white medullary sub- stance of the brain, spinal marrow, and the nerves proceeding from them, is the immediate instrument of sensation and motion. External objects excite vibrations in the medullary cord, which are continued by a certain elastic ether. Connected with this theory are other doctrines, especially that of association, which gave to Dr. Hartley a reputation as one of the most in- anious metaphysicians of the 18th century. 7 hen a sensation has been frequently expe- jnced the vibratory movement from which it rises acquires a tendency to repeat itself spon- ineously. Ideas are but these repetitions or slics of sensation, and in their turn recall other ideas. By the development of the law of as- >ciation, and chiefly by the law of transfer- ice, he accounts for all the phenomena of the lental constitution. In many cases, the idea rhich is the link of association between two ler ideas comes to be disregarded, though association itself remains. Thus the idea >f money is connected with that of pleasure 3y the conveniences which wealth may supply ; >ut the miser takes delight in money without linking of these conveniences. In this way [artley accounts for almost all the human emotions and passions. An edition of the work, by his son, with notes from the German of H. A. Pistorius, was published in 1791 (3 rols., London). II. David, son of the preceding, >rn in 1729, died in Bath in 1813. As mem- ber of parliament for Kingston-upori-Hull, he lily opposed the war with the American colonies. He was one of the plenipotentiaries appointed to treat at Paris with Dr. Franklin, in whose correspondence, published in 1817, some of his letters appear. He was an early promoter of the abolition of the slave trade, and exhibited his scientific knowledge in sev- eral useful inventions. HARTBIAM, Ednard von, a German philoso- pher, born in Berlin, Feb. 23, 1842. He was lucated at the gymnasium in Berlin, and sub- juently at the school of artillery. He be- rnie an officer in 1861 ; but having hurt his >ot accidentally in the following year, and an icurable disease setting in, he has since been lost entirely confined to his room. Devo- ting himself to literary 'pursuits, he has pub- " "led several philosophical works, and among lem Die Philosophic des Uribewmsten (Berlin, L869; 5th ed., 1873), by which he has gained a slace among the foremost thinkers of the age. e contends that philosophy must seek cor- poration from results inductively obtained in le physical sciences. He assumes that there in nature an unconscious will and idea as a jure and spiritual activity, without a substra- tum of nerve or brain, which is the basis of consciousness. The same unconsciousness he finds in spirit, in the human instinct, sexual love, emotions, morals, aesthetics, and thought, in the development of language, sensual perceptions, HARTSOEKEK 491 mysticism, and history. His metaphysics teach that unconsciousness is the last principle of j philosophy, described by Spinoza as substance, I by Fichte as the absolute I, by Schelling as the absolute subject- object, by Plato and Hegel as the absolute idea, and by Schopenhauer as the will. The attributes of the unconscious spirit are will and idea, and the world is the product of both. He affirms that it is neither possible for Hegel's " logical idea " to attain to reality without will, nor for Schopenhauer's "irra- tional will " to determine itself to prototypal ideas; and he demands, therefore, that both be conceived as coordinate and equally legiti- mate principles, which after the precedent of Schelling are to be thought of as functions of one and the same functioning essence. The end of development is the turning back of vo- lition into non-volition, which is attained by means of the greatest possible intensification of consciousness, resulting in the emancipation of the idea from the will. Among Hartmann's minor publications are several poetical produc- tions. HARTMANN, Moritz, a German poet of Jewish parentage, born at Duschnik, Bohemia, Oct. 15, 1821, died in Vienna, May 13, 1872. He studied in Prague and Vienna ; but umbrage being taken at his liberalism, he left Austria, and published a volume of patriotic poems, Kelch und Schwert (Leipsic, 1844), which was followed in 1847 by Neuere Oedichte. In 1848 he was a prominent liberal member of the Frankfort parliament, and accompanied Froe- bel and Blum to Vienna, whence he escaped after the execution of Blum, and travelled ex- tensively, spending a considerable time in the East during the Crimean war, and several years in Paris. In 1860 he delivered lectures on German literature and history in the acad- emy of Geneva. In 1863 he removed to Stutt- gart, and in 1868 to Vienna. Among his best known novels are : Der Gefangene von Chillon (1863) ; Die letzten Tage eines Ednigs (1866), which has been translated into English ; and Die Diamanten der Baronin (2 vols., 1868). Of his political writings the most notable is Eeimchronik des Pfaffen Mauritius (1849), a satire on the Frankfort parliament, written in the manner of the old rhyming chronicles. A complete edition of his works was published at Stuttgart in 10 vols. in 1874. HARTSHORN, Spirits of. See AMMONIA. HARTSOEKER, Nicolaas, a Dutch philosopher, born in Gouda, March 26, 1656, died Dec. 10, 1725. He was intended for the church, but devoted himself to scientific pursuits. One of his earliest inventions was an improved form of object glasses for microscopes, which enabled him to discover animalcules in the animal fluids, on which a new doctrine of generation was formed. Subsequently in Paris he succeeded in manufacturing object glasses for telescopes superior to any previously made. An account of these discoveries was published in the Jour- nal des Savants of Paris by Huygens, and in
