86 Bylandt''s Resume Preliminaire de VOuwage 



The same division is made from the Gulf of Mexico as 

 a centre, and a similar result obtained, (p. 20.) The cur- 

 rents of the ocean are attributed to the volcanic action, which 

 is said to correspond exactly with the lines of magnetic and 

 aerial phenomena, (p. 22.) The author flatters himself that 

 he has discovered a volcanic canal flowing round the globe 

 between two parallels, and concludes that volcanoes are like 

 knots on a string, which must partake any shock commu- 

 nicated to either extremity (p. 24.), quoting his examples 

 from the known localities, (p. 26.) 



He next proceeds to examine the nature of the volcanic fire, 

 which, he says, is purely material, arising from infiltration 

 and fermentation (p. 26.) of gases, and water, and the mate- 

 rials of the strata it traverses ; these being dissolved, com- 

 bined, and reunited. To volcanoes acted on by the sea, 

 the author attributes the great partial catastrophe which has 

 desolated our hemisphere, and which, by the junction of the two 

 oceans, under the name of the great cataclysm (the deluge), 

 has produced the diluvial effects which the earth exhibits, 

 (p. 28.) He explains by this means the currents directed 

 towards the west, and the immense ravages in the coasts of 

 the continents of Africa, America, and Europe, and the 

 separation of the two former quarters of the globe, once 

 united, as proved by the traces of African civilisation in 

 Mexico, (p. 30.) The elevation of mountain chains is also 

 made to result from this cataclysm^ and the Pyrenees are 

 quoted as the example, (p. 31.) 



M. de Bylandt next classifies volcanoes into — I. Sub- 

 marine ; II. Volcanoes " a de convert ; " which are subdivided 

 into — 1. Direct volcanoes, situated on the great canal; 2. 

 Indirect, on the extremities of the lateral branches ; 3. Vol- 

 canoes in permanent action ; 4, Extinct or mud volcanoes ; 

 5. Volcanoes of air ; 6. Volcanoes of smoke ; 7. False vol- 

 canoes, or simply burning hills (such, we suppose, as the 

 cliffs near Weymouth), (p. 32.) 



A long illustration of another position follows, namely, 

 that the size and height of volcanoes are proportioned to 

 the force of the volcanic fire and the depth whence it rises. 

 The formation of volcanic cones is next mathematically shown 

 by a system of triangles upon the base of the volcano, and the 

 height of the cone and depth of the crater proved to be pro- 

 portionably determined by a general law, whilst the depth of 

 the crater is made to be a third part of the primitive height 

 of the volcano, (p. 35.) Here, again, we are a little at fault. 

 Vesuvius is the subject of the experiment to exhibit the truth 

 of these theories. 



