The great mountain range of the Apennines, mainly of granite formation, extends through the central part of Italy. The lands adjoining the mountains on each side are flat and marshy, and consequently unhealthy. Numerous observers have compiled excellent accounts of the Calabrian earthquake. These, having been made by educated persons, are, to a large extent free from the inconsistencies and exaggerations apt to characterize descriptions by ignorant persons, especially when in a condition of excitement or alarm. Among reliable writers was Sir William Hamilton, who made a personal examination of the region, soon after the first severe shock, and collected much valuable information for a paper which was afterwards published in the Philosophical Transactions of the Royal Society. Then, too, Dolomieu, another scientific man of high ability, made a careful study of the effects produced by the earthquake. [Illustration: FIG. 42. MAP OF THE CALABRIAN EARTHQUAKE OF 1783] As can be seen by an examination of the map presented in Fig. 42, the part of Italy included in the Calabrias covers an area from north to south almost equal to two degrees of latitude. Although the shock extended beyond the limits of Calabria, since it reached as far north as Naples, as well as over a great part of the Island of Sicily, the territory in which the greatest damage was done did not exceed in area about 500 square miles. The southern part of Italy is subject to frequent earthquake shocks. Pignatari, an Italian physician, asserts that this region was visited during 1783 by no less than 949 earthquakes, of which 501 were of the first class, or degree of intensity, while in 1784, there were 151 earthquakes, of which ninety-eight were of the first class. It seems that the city of Oppido, marked on the above map as midway between the two coasts, was the point from which the severe earthquake of 1783 started. If one draws a circle, with a radius of twenty-two miles, around Oppido as a centre, the portions of the Calabrias that were the most affected will all lie within this circle. The great Calabrian earthquake was attended by numerous shocks. The first and the most severe shock, that of February 5th, 1783, was only two minutes in destroying most of the houses in all cities, towns, and villages on the western side of the Apennines in this part of Italy. Another severe shock occurred on the 28th of March. This shock was almost as severe as that of February 5th.