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The author we have already fpoken of, alTures us there is abfolutely no other critical 

 time, than that of the fix hours and fome minutes the moon takes up to pafs the horary 

 circle between three and nine. This is precifely the time of reflux : for it is full fea 

 upon almoft all the coaft of South America in the South Sea, when the moon paflfes the 

 horary circle at three. But let us examine how many different circumftances muft 

 concur to prove that our author's rule mult be an exadt one. It is neceflfary the focus 

 of the fire be always in the fame place ; the water muft always take the fame courfe, 

 enter always with the fame celerity, and that the mixture ever take up exadly the fame 

 portion of time to enflame. If it is not neceflfary that all thefe circumftances fliould 

 concur, very exaft compenfation (hould at leaft be made to fupply the defed. The 

 earthquake, alfo, of the year 1 746, which occafioned the deftru6lion of Lima, did not 

 happen while the moon was on her way of the horary circle between three and nine, 

 but, on the contrary, while ftie was pafTing the fame circle between nine and three. 

 The tragic period is not lefs falfe. The author pretends, that nothing is to be appre- 

 hended but when the horns of the moon are found in the malignant figns.of Scorpion, 

 or Amphora ; whereas thefe horns were then in the figns of the Virgin and Pifces. 



There are few weeks during which fome flight fhocks of an earthquake are not felt ; 

 if it is not in one place, it is in another ; frequently no perfon pays any attention to 

 them, nor gives himfelf the trouble to colled: or mark their dates. An aftrologer, 

 therefore, is at full liberty to boaft, that the obfervation has never been at variance with 

 his conjeftures. The only earthquakes to be dreaded by him are thofe attendant with 

 the moft difaftrous confequences. Happily thefe are rare, and may, after all, happen 

 as well at one feafon as at another. They have always the wife precaution, not to con- 

 fine their prognoftications within too narrow bounds ; and befide that, the pretended 

 rule ought at leaft to quadrate with fome one precedent calamity, with thofe upon which 

 they form them. 1 



After all, if we would proceed with any method to difcover if there is really a period 

 that may be denominated tragic, we muft go another way to work. We fiiould begin 

 by the examination of the fimpleft fafts : the firft objed of our obfervations, it feems 

 to me, fliould be the eruptions of the volcanos. In truth, with refpedt to the return of 

 earthquakes, the events are extremely complicated ; they may be tranfmitted folely by 

 the contiguity of lands, though they be very remote from the point which correfponds 

 to the upper focus of the eruption. In every place fliocks are felt around to a certain 

 diftance, and yet we are ignorant where particularly to fix its origin : whereas the points 

 of volcanoes are more determinate in every country, and, confequently, fupply us with 

 lefs equivocal obfervations. Any regular returns of thefe eruptions have never been 

 remarked ; and this muft neceflarily be the cafe with refpect to earthquakes, which, for 

 the reafons we have ftated, are lefs under the controul of any rules, and becaufe that, 

 in every place, they muft depend upon a great number of cafualties. The rain-waters 

 very often produce the fame effeds as the fea-water, and it fhould be conlidered, it is 

 in the latter months that the rains fall the moft in the countries we are fpeaking of. 

 Sometimes a very violent fliock in the Cordelier is felt but over a very confined fpace. 

 There is then reafon to imagine the inflammable mafs lies very deep, and that the fea has 

 no immediate connedion with the accident. Both the fea and rains contribute to many 

 ftiocks, which is a double reafon they (hould be very frequent. 



A comparifon of volcanic eruptions with earthquakes throws fome light upon many 

 particulars of thefe laft phenomena. Volcanoes, when in flames, ad, as it were, by 

 fits ; the flarhe or fmoke is feen to ilTue by whiffs or blafts. When I was engaged on 

 one of our ftations at Senegualap, my night's fleep was continually interrupted by the 



VOL. XIV. R R roaring 



