The terms synchronism or synchronous, as here used, are not designed to imply absolute simultaneity (although that is sometimes the case with disturbances 180° apart), but are rather intended to indicate the tendency presented by these phenomena to exhibit this internal activity, during successive days, weeks, or even months, along a given great circle of the earth, especially one or more of those connected with the land center; perhaps most of all along the great circle which forms the prime vertical, when the center of land is placed at the zenith. In order to test the above, let us examine the record of the most prominent earthquakes or volcanic eruptions for the year 1883. Late in Dec., 1882, and early in Feb., 1883, shocks occurred in New Hampshire; on Jan. 11, 1883, also at Cairo, Illinois, and about the same time at Paducah, Ky.; Feb. 27 at Norwich, Conn., and early in Feb. at Murcia, Spain. These, by examination of any good globe, will be found on a belt forming one and the same great circle of the earth. Late in March and during part of April the volcano of Ometeke in Lake Nicaragua was active (after being long dormant); Panama, portions of the U.S. of Colombia, and of Chili; also, in May, Helena, M.T.; and, in June, Quito (with Cotopaxi active) were all more or less shaken by earthquakes; and are all found on one belt of a great circle. The principal record for the remainder of the year comprised: An earthquake at Tabreez in North Persia, early in May, 1883. The awful destruction in Ischia, July 29 (with Vesuvius active). The fearful eruption in the Straits of Sunda, 25th Aug. and later. Shocks in Sumatra and at Guayaquil, about same date or early in Sept. Shocks at Dusseldorf, according to a Berlin paper of 5th Sept. Shocks at Santa Barbara and Los Angeles, early in Sept. Shocks at Gibraltar and Anatolia in October. Shocks at Malta, Trieste, and Asia Minor in October. Azram shaken late in Sept., and great destruction between Scios and Smyrna. Lastly, the formation of a new island in the Aleutian Archipelago. Date of outburst, early in October, 1883. Besides these, there were several other less severe disturbances, the records of which are chiefly obtained from Nature, and which will-be referred to below. If the globe be so placed as to have the land center at the zenith, the exact position of the new island, near Unnok, will be found under the brazen meridian, while Agram, Tabreez, Sunda, Sumatra, Quito, and Guayaquil are all on the prime vertical.