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of about 600 tomoli of ground. It is known that a tomolo line measure is equal to 5.88 moggia of legal measure. Similar fissures have been discovered in the mountain of Ariosa before mentioned, and in other territories of different communes: it is no unusual effect of earthquakes. One circumstance excited great astonishment, viz., that in many wells in Potenza, and the adjacent communes of the province, a month before the earthquake, the accustomed volume of water was most remarkably diminished, and several wells were completely dried up. This phenomenon frequently serves as a salutary warning to the people residing in the vicinity of Vesuvius; with us it did not excite a shade of suspicion, for every one accounted for the failure of the supply, by imagining the usual known or unknown causes, without investigating the matter any further; and being considered of slight importance, it did not become a subject of public discourse. Amongst others, one well which, to my certain knowledge, was full of water in September, and increased by the heavy rains in October, was dry in November. If we consider that these wells have no channel through which the water could be dispersed, it is evident, that only a remarkable increase of caloric in the strata beneath could occasion this, either by evaporation, or absorption (which appears to me the more natural) of the strata. Another opposite fact is the increase of spring water subsequently to the earthquake, observable, among other instances, in the public fountain of Potenza and the water of the adjacent river. This is a manifest difficulty. If the water has been absorbed, and decomposed by a subterraneous fire, how can it afterwards return more impetuously and abundantly than ever? I shall venture an opinion at the risk of being excommunicated by natural philosophers, who explain the phenomenon in a different manner, and will say that when the water fails, it has been absorbed by aspirazione from above, and by the porous earth beneath; and when the water increases, a contrary force (l'impulso) urges it to flow back again. If these forces have been observed by Franklin and more modern philosophers in hurricanes, tempests, and whirlwinds, without their being able to account for them, my conjecture might at least serve to classify, under the same rule, a phenomenon which does not admit of complete ex-