HAKTINGTON. 601 HARTLEY. east of Yankton, S. D. ; on the Chicago, Saint Paul, Minneapolis and Omaha Railroad (Map: Nebraska, G 1 ) . It is the centre of a farming and stockraisinp district, and has scftne manufac- tures. Population, in 1900, !I71. HARTINGTON, Marqiis of. See Devox- siiiRE, Eighth Duke of. HARTLAXJB, h-irt'loup, GusT.w ( 1814-1900) . A German ornithologist, born in Bremen, and educated at Berlin, Bonn, and Giittingen. In ad- dition to his contributions on ornithology to Troschel's Aicliiv dcr atui-;icschirhtc during a period extending from 1846 to 1871, he published several valuable scientific works chietlv on the birds of Africa. These include: fv King .Tohn. Population, in 1891, 21.300: in loo'l. 22.700. Consult Sharjie. History of Ri'rtlepool (1800: new ed. 18.51). HARTLEPOOLS, The. A Parliamentary bor- ough and jiort of Durham County, England, com- prising the municipalities of Hartlepool (q.v.) and its extension. West Hartlepool (q.v.). HART'LEY, Sir Charles Augustus (1825 — ) . An English engineer and railroad-builder. He served through the Crimean War as captain of engineers in the Turkish contingent: was made engineer-in-chief of the European Commis- sion of the Danube in 1856. and in 1862 was knighted. In 1867 he drew up plans for the enlargement of the harbor of (Ddessa. and won with them the competitive prize of 8000 silver riililes olTered by the Emperor of Russia. In 1875 he was a member of the board of engineers appointed by the President of the United States to report on the practicability of .J. P>. Eads's plan for improving the south pass of the Mississippi River by means of jetties. The British Govern- ment named him a member of tlie International Technical Commission on the Suez Canal in 1884. As a consulting engineer he was employed by several governments, notably on the harbor and river improvements of the Hugli, the harbor of Triest, the Nile Barrage below CaJK), and the harbor of Varna. Among his published works are: Delta of the Danube; Public Works in the United States and Canada; Inland Saviyatioii in Europe ; and History of the Engineering Works of the .Sue; Canal. HARTLEY, David (1705-57). A celebrated English philosopher. His father was Vicar of Armley, in Yorkshire. At fifteen he entered Jesus College, Cambridge, and afterwards became a fellow of the college. He studied at first for the Church, but dissented from some points in the Articles, and in consequence had to abandon his original intention. He finally chose the profession of medicine, in which he attained considerable eminence. He practiced as a physician suc- cessively in Newark, Bury Saint Edmunds, Lon- don, and Bath, where he died. His chief work, entitled Observations on Man, His Frame, His Duty, and His Expectations, was begun when he was about twenty-five, and occupied him for six- teen years. It was published in 1749, and was translated into French and German. The first part relates to the constitution of the human mind, and is the really important and original part. The second part treats of religion and morals. His handling of the mind turns throughout upon two theories. The first is called the doc- trine of vibrations, or a theory of nervous action analogous to the propagation of sound, the sug- gestion of which he owed to Newton, of whose writings he was a student. The second theory was that the higher activities of the mind might be explained to a very wide extent by the prin- ciple of the association of ideas (see Association OF Ide.s) — a principle far from new in the state- ment of it, but never before appreciated in any- thing like the range of its bearings upon the phenomena of mind. The doctrine of vibrations supposed that when any one of the senses was affected by an outward object, the effect was to set the particles of the nerve in a vibratory motion, which ran along to the brain, and produced corresponding vibra- tions in the cerebral substance. In like manner, when an active impulse proceeded outward to the muscles, the manner of communication along the nerves was of the same kind. He even ex- tended these molecular vibrations to the other tissues. All conscious processes were regarded as having physiological correlations in brain proc- esses. The opposition that immediately mani- fested itself against t4iis part of Hartley's specu- lations arose from a mistaken notion that it favored materialism. As regards the second doctrine of Hartley, the doctrine of association, he has the right to be regarded as the fomider of the English school of association, although thinkers before him. among whom were Locke and Hume, had used the prin- ciple of association to explain many of the more developed mental contents. But it seems that Hartley was the first to make association a prin- ciple for the explanation of all complex psychical phenomena. He maintains that it is involved in the conversion of our sensations into ideas, and
