J3(J ON EXTINCT VOLGANOES, 



trivance and the fly, as far as concerns one fingle revoliw 

 tion, whether they be confidered as regulating any one of 

 thefe. In both, the furplus power is employed in putting 

 a weight into a fituation or ftate by which it is enabled to 

 give back (in theory) the fame furplus, when therefiftance 

 becomes greater or the power lefs. But if the whole power, 

 in ieveral fucceflive revolutions, fliould exceed the refiftance, 

 ^nd produce acceleration, the fly w'iH continue to accumu- 

 late niQinentum, and will be ready to give it out, againft 

 an augmented refiftance in fucceeding revolutions ; fo 

 that its eiualizing power extends not only through each 

 iingle revolution, but through many. I do not perceive this 

 property in the ingenious contrivance before us. 



XIL 



Ohfervations on the extinB Volcanoes in the Environs of Coblentz, 

 by the Chevalier de Sade. Tranjlated from the original 

 Mariufcript, communicated by the Count rfe Bourn on. 



Coblentz built WhEN I refided at Coblentz in 1791, the volcanic 

 of volcanic ftone,f^Qj^gg made ufe of in that city, led me to inquire whence 

 from the neigh- *'"'^J Were procured. I was foon informed, that they came, 

 lourhood of from the neighbourhood of Andernach ; and the clergyman 

 " ""^*^ * of that place acquainted me, that the extin6l volcanoes 

 gions faid to have were near Haach, an abbey of Benedidine monks, three 

 been driven from leagues diftant. This worthy gentleman added, that he 

 Andernach j^b^ ^^^ fomewhere feen it mentioned, that the Roman legions, 

 a volcano. encamped near Andernachj^ were obliged to quit their poft^^ 



able! ^^^ ^^^' ^^ account of the fire ilTuing from the volcano. Its great 

 The extinftvol- diftance from the fea, made m^ doubt the truth of this ; and 

 th'^^^V^^V'^ my own obfervations have convinced me, that the extinct 

 vergne, of, on- volcanoes of this country are at length as ancient as thofe of 



known date. Auvergne, the date of which is unknown. 

 Beyond Ander- ^_ ? , ., , ,. ^. 



rach, river fe- Having procured a guide, and directing my fteps to- 



diment inter- ward the fouth, I had fcarccly quitted Andernach, before 

 inicrftones ^d \^^^ with river fediment, intermingled with pumice ftone.*^ 

 ■volcanic fands. and volcanic fands. Leaving the high road, I proceeded 

 fmaTmo^ntain ^^^^^^^'^ ^ imd\\ mountain on the weft, called Agemberg. 

 Oil the >veit. f ft 



