360 EARTHQUAKE don on the Neapolitan earthquake of 1857, which was published in 1862 under the title of " First Principles of Observational Seismol- ogy." Numerous special or general catalogues of earthquakes have been published, of which we note those of Von Hoff, Cotte, Hoffmann, Merian, and especially the great catalogue of Mallet, "The Earthquake Catalogue of the British Association," which very complete record embraces between 6,000 and 7,000 earthquakes recorded between the years 1606 B. C. and A. D. 1842. For the interval 1842 to 1872 the catalogues compiled by Perrey and published from time to time in the transactions of the Belgian royal academy form an almost ex- haustive record. The special catalogues of Per- rey for southern Europe, of W. T. Brigham for the United States, &c., may also be consulted. The catalogue by Scrope in his treatise on vol- canoes (2d ed., revised and enlarged, 1872) is Siite trustworthy for the most recent dates, f theoretical works on the nature and origin of earthquakes there is scarcely any end, but among the few who have really advanced this branch of knowledge we may mention Dr. Thomas Young and Gay-Lussac, who seem to have remarked the similarity between earth- quake shocks and the vibrations of sounding bodies, and Mr. Mallet, who, viewing all the phenomena with the eye of an expert mechani- cal engineer and by the application of rigidly exact measurements and inductive reasoning, has undoubtedly succeeded to a remarkable de- gree in perfecting our views of the forces act- ing during an earthquake, and advanced our knowledge of the ultimate origin of the initial disturbance. The intimate connection between the phenomena of geology on the one hand and of volcanoes and earthquakes on the other has been treated of with more or less ful- ness by Babbage, FJie de Beaumont, Leopold von Buch, Dana, Darwin, Daubeny, Forbes, Herschel, Hopkins, Hottingen, Humboldt, Hunt, Lyell, Murchison, Phillips, Eitter, Ro- gers, and Scrope ; and the established laws of dynamics, of heat and of strength of materials, have been applied with much success to the question of the origin of these disturbances by Haughton, Hopkins, Oldham, Provost, Thom- son, and especially by Mallet (see his preface to Palmieri's " Vesuvius," London, 1873). Of general treatises, that by Prof. J. D. Whitney, " Earthquakes, Volcanoes, and Mountain Build- ing" (New York, 1871), and that by Prof. Boccardo, Seismopirologia (Genoa, 1869), are among the most recent. The essay by Mallet lately presented to the royal society promises when printed in full to mark an epoch in the science of seismology. Interesting matter will also be found presented in a popular style in Reclus on "The Earth." Memorable Earthquakes. In southern Italy and Sicily no century has elapsed since the earliest periods of history that has not been distinguished by severe if not frequent earthquakes. From 1773 to the end of 1776 this region was almost constantly disturbed ; no fewer than 947 shocks were experienced in the first of these years, of which 501 were of the first degree of force. Lyell observes that great importance attaches to these from the minuteness of the observa- tions of men competent to collect and describe with accuracy the physical facts that throw light on geological questions. The great earth- quake of 1783 in Calabria probably caused the death of 100,000 persons, and was felt in a great part of Europe ; it was fully described by the commission of the Neapolitan academy. The origin of the shock was at a spot under the centre of Calabria ; the disturbance passed under the sea without producing any great sea wave, but on reaching the opposite coast of Sicily destroyed the city of Messina. The de- structive sea wave that entered the harbor of the latter city was not propagated across the sea, but was probably caused by the dislocation of large masses of rock that fell into the waters near Messina. In central Italy, among the ear- liest of the recorded earthquakes is that of the year A. D. 63, which resulted in the partial de- struction of Herculaneum and Pompeii, 16 years previous to the time when those cities were buried under the lava and ashes accompanying an eruption of Vesuvius. The earthquake of 1857 in the kingdom of Naples is the most note- worthy that has occurred there during the present century, not only because of its extent and fatal violence, but even more so because of the masterly investigation to which its pheno- mena were submitted by Mallet on behalf of the British association for the advancement of science. This earthquake was felt throughout the kingdom of Naples ; in the city itself com- paratively slight damage was done, the chief scene of the destruction being in the provinces. The velocity with which the wave of shock spread in all directions from its origin near the town of Potenza was about 775 ft. per second. Of the many suggestive results of Mallet's investigation we shall have occasion to speak further on. The earthquake of 1855, known as the earthquake of Vie"ge, has been carefully studied by Volger. It was felt slight- ly in Paris, Mentz, and Geneva ; the region of greatest violence was between Bern, Lugano, and Chamouni ; the velocity of translation of the wave of shock was northward 2,861 ft. per second, but southward only 1,391 ft. On Nov. 14, 1861, another great earthquake occurred in Switzerland, simultaneously with which it was noticed that in the artesian wells at Passy, Paris, the sediment suddenly increased from 956 to 2,268 grains per cubic metre, after which it began to decrease. In general it has been noted that the springs of this place are simi- larly affected by almost every earthquake of western Europe. In Portugal, the city of Lis^ bon was visited on the morning of Nov. 1, 1755, by one of the most memorable earth- quakes recorded in history. The rumbling sound that precedes most earthquakes was im- mediately followed by the great shock which
