prevalent Disorders, fyc., with Volcanic Emanations* 159 



tinian; 1800, 1817, and 1833, periods of pestilence; 1245, 

 the astronomical year of Mrs. Somerville; 1333 and 1348, 

 the limits of the Black Death epoch; with 1420, 1289, 

 and 1189 (the latter within a year), periods named in the 

 German Chronicles ; 51, the prophetic year of famine in the 

 days of Claudius ; 365, the year of earthquakes all over the 

 globe; and 18, the date assigned by Tacitus for the ruin of 

 the cities of Asia. The calculation gives, also, the years b. c. 

 195, 202, 213, and 219, the identical years named by Livy and 

 Tacitus, extracts from whom will follow in a future paper; 

 and the year 103, in which year, Pliny (II. 57.) says, extra- 

 ordinary lights were seen in the sky, during the third con- 

 sulship of Marius. 



It is, I think, impossible, that such a result should be 

 obtainable, without there being a positive periodicity in the 

 derangement of the earth and atmosphere ; and such being 

 the case, why should we refer the meteors of Nov. 12. 1799, 

 1832, 1833, and 1834, to a comet, when the earth can answer 

 all demands upon it ? I am not one of those who think that 

 this earth, adapted as it is in all things for the purposes of its 

 creation, is in any respect otherwise than under the guidance 

 of those general laws by which its motion and phenomena 

 are regulated ; nor can I believe that earthquakes or volcanic 

 eruptions occur by chance, which they suppose who deny a 

 regulating law in these occurrences. Whatever be the laws 

 which guide its internal economy, we have no revealed do- 

 cument to appeal to; it is by enquiry and patient observation 

 alone that we can arrive at the truth, and the facts which oc- 

 cur are the alphabet from which the history of our knowledge 

 is to be composed. There may be wise and merciful reasons 

 in the Almighty Mind, why the seasons and the climates 

 undergo certain changes, which we, for want of instruction, 

 consider extraordinary ; and thus, one period may be dry and 

 another wet, one hot and another cold, to preserve that equi- 

 librium which we cannot fail to perceive as the regulator of 

 nature in all her departments ; and the earth may be, and pro- 

 bably is, so constructed, that one phenomenon must, in excess, 

 produce another; and thus the vicissitudes which form the sub- 

 jects of our speculation are literally, perhaps, only the regular 

 movements of the great machine, by which its course is pre- 

 served uninjured, and the promise of the Creator kept towards 

 the productions of his infinite and foreknowing skill. (" While 

 the earth remaineth, seedtime and harvest, and cold and heat, 

 and summer and winter, and day and night, shall not cease." 

 Gen. viii. 22.) He who ordained this, can surely produce it as 

 he will; and it is certainly more rational to suppose the laws 

 of which this promise is the proof are impressed upon the earth, 



