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 498 BELL which is the thickest part, being equal to 1, the height should be 12, the diameter at the mouth 15, the diameter of the top 7i, and the weight of clapper ^ of that of the bell. The tone is regulated by the thickness, a thick bell having a higher note than one that is thin. As the precise pitch cannot be attained in casting, the bell is toned afterward, either by reducing the thickness where the hammer strikes, to produce a lower note, or by chipping away the edge and reducing the diameter to make it more acute. In conformity to the laws of acoustics, the number of vibrations of a bell varies in inverse ratio with its diameter, or the cube root of its weight ; so, for a series of bells forming a complete octave, the diam- eters should go on increasing with the depth of tone, as for do, 1 ; re, f ; me, $ ; fa, ; sol, bells, by the Eev. W. C. Lukis, appeared at London in 1857. The Rev. Alfred Gatty has published "The Bell, its Early History and Uses" (London, new ed., 1848), and Mr. E. B. Denison's "Lectures on Church Building" treats of bells. BELL, a central county of Texas, watered by Little river and its head streams, the Leon and Lampasas ; area, 1,097 sq. m. ; pop. in 1870, 9,771, of whom 1,104 were colored. It has a rolling surface, and a soil of sandy loam, well adapted to pasturage. Forests of cottonwood and live oak cover about one fourth of the county. There are several chalybeate springs. The chief productions in 1870 were 358,360 bushels of Indian corn, 14,296 of sweet pota- toes, 2,896 bales of cotton, and 19,575 Ibs. of wool. There were 7,425 horses, 4,430 milch cows, 1,494 working oxen, 30,976 other cat- tle, 9,718 sheep, and 12,467 swine. Capital, Belton. BELL, Andrew, an English clergyman, born at St. Andrews, Scotland, in 1753, died at Chel- tenham, England, Jan. 27, 1832. After study- ing in St. Andrews university, he visited America, and in 1789 went to India, where at Madras he became chaplain of Fort St. George. He found in the mission schools of India a monitorial system, which on his return to Eng- land he proposed for adoption into English schools. It consists in a division of the school into classes, and of the classes into pairs, the two members of a pair being each pupil and tutor of the other. It was not, however, till an analogous system had been introduced by the Quaker Joseph Lancaster into the schools of the dissenters, that Dr. Bell was authorized by the English church to employ it in schools under his charge. He published several works upon educational subjects, and left his fortune (amounting to more than 120,000) for the en- dowment of schools. BELL, Sir Charles, a British surgeon and anat- omist, born in Edinburgh in November, 1774, died at Hallow Park, Worcestershire, April 29, 1842. He began his education in the high school and university of his native city, and pursued his professional studies under his elder brother John. He was admitted in 1799 to the college of surgeons, became at the same time one of the surgeons to the royal infirmary, and while still a youth delivered lectures be- fore 100 pupils on the science of anatomy. He removed in 1806 to London, where he imme- diately began a course of lectures, and rapidly rose to distinction. He now published his work on the "Anatomy of Expression," which was designed to show the rationale of those muscular movements which follow and indicate the excitement ef the various passions and emo- tions. His "System of Operative Surgery" was published in 1807. He supported himself unconnected with any medical schools till 1811, when he was invited to the Hunterian school, and three years later he was appointed surgeon to the Middlesex hospital, an institution which during the 22 years of his connection with it he raised to the highest repute both by his striking manner of lecturing and his great dex- terity as an operator. He visited the fields of Corunna and Waterloo immediately after the battles, and gave his services to the wounded. In 1821 he produced his ideas on the nervous system in a paper in the " Philosophical Trans- actions." It immediately arrested the atten- tion of anatomists throughout Europe, some of whom contested with him the priority of discovery; yet it was fully proved that Dr. Bell had taught the doctrine for many years to his pupils, had explained it in a pamphlet, a private edition only of which was printed, in 1810, and had clearly stated it in letters to his brother in 1807, when all his rivals were teach- ing the old theory. The principle of the dis- covery is that there are distinct nerves of sen- sation and of motion or volition, one set bear- ing messages from the body to the brain, and the other from the brain or will to the body. It was shown by Dr. Bell that the brain and spinal marrow are likewise divided into two parts, which minister respectively to the func- tions of motion and sensation ; that those roots which join the back part of the spinal marrow are nerves of feeling, messengers from the senses, but incapable of moving the muscles, while those roots which have their origin in the front column of the spinal marrow and the adjacent portion of brain are nerves of vol- untary motion, conveying only the mandates of the will. He showed that though three distinct nerves may be bound together in a sin- gle sheath for convenience of distribution, they yet perform different functions in the physical economy, and have their roots divided at the junction with the brain. The nerves of the different senses are connected with distinct portions of the brain. For this discovery Bell received a medal from the royal society of Lon- don in 1829, and upon the accession of William IV. he was invested, in company with Brews- ter, Herschel, and others, with the honor of knighthood, in the new order then instituted. He was also made senior lecturer on anatomy
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