PITCH 260 PITCH session of by nine of the mutineers of H. M. S. "Bounty," with six Tahitian men and 12 women, the ringleader being called Christian. Four years later the native men one night murdered all the Englishmen, except Alexander Smith, who afterward assumed the name of John Adams. Thereupon the women, in revenge, murdered all the Tahitian men. At the end of 10 years John Adams was left alone, vdth eight or nine women and several children; and from them the present inhabitants (126 in 1890) are descended. Adams, changed by these tragic adventures, set about the education of his companions in Chris- tian principles. The little colony was unknown to the world till 1808, when it was "discovered" by Captain Folger of the American sealing ship "Topaz"; the first British vessel to visit it did not arrive till 1814. The islanders were vis- ited again in 1825 and 1830, and in 1831, as their numbers had rapidly increased (to 87), they were at their own request removed to Tahiti by the British Gov- ernment. But, disgusted by the unde- sirable customs of their Tahitian rela- tives, the most of them went back to Pitcairn Island. The island was an- nexed to Great Britain in 1839. Nearly 200 of the islanders were transferred to Norfolk Island in 1856, but a number of them afterward returned. Pitcairn Is- land enjoys a lovely climate; its moun- tainous surface reaches 1,008 feet in Outlook Ridge; the soil is fertile, and produces yams, cocoanuts, bread fruit, sweet potatoes, bananas, etc. Pop. (1914) adults, 140 males, 39 females; children, 66. PITCH, a term applied to a variety of resinous substances of a dark color and brilliant luster, obtained from the va- rious kinds of tar produced in the de- structive distillation of wood, coal, etc. In architecture, the rise or versed sine of an arch. In carpentry, the inclina- tion of a roof. The common pitch has a rafter three-quarters the length of the span; the Gothic has a full pitch; the rafters being the length of the span; the Greek has a pitch % to ^ of the span ; the Roman has a pitch from % to % of the span; and the Elizabethan has raf- ters longer than the span. In hydraulic engineering, in overshot water wheels the bucket-pitch is a circu- lar line passing through the elbows of the buckets. The elbow is the junction of the floor and the arm, which together form the bucket. In machinery: (1) the distance between the threads of a screw measured on a line parallel to the axis. (2) The distance between the centers of two adjacent teeth in a cog- wheel, measured on the pitch circle. (3) The pitch of a rivet is the distance apart from center to center. (4) The distance between the stays of marine and other steam boilers. In marine boilers it is usually from 12 to 18 inches. In mining, a lode or portion of SIR ISAAC PITMAN a lode let out to men to work by the piece or by a percentage of the output. In music, musical sounds give to the mind a feeling of acuteness or gravity according to the rapidity or slowness of the vibrations producing them; hence, the former are called acute or high, the latter grave or low. The absolute pitch of sounds is measured by giving the number of vibrations per second which produces a given sound, e. g., C = 528; the relative pitch of sounds is described by giving the ratio of vibrations of the interval, e. g., a fifth is 2:3 — that is, the higher sound of any interval of a fifth gives three vibrations, while the lower sound in the same time gives two. The determination of fixed pitch is purely arbitrary, and it has from time to time undergone great variations. In England we have high concert pitch C = about 540, more or less, and the medium pitch C = 528 ; on the Continent the French "diapason normal," C = 518, is being largely adopted. The official standard adopted in the United States during the world's fair was what is known as inter- national or "French" pitch, which gives as a standard middle A with 435 vibra- tions, though the majority of American
