SALSES. 209 



separated from the continent by a channel of 30 feet in 

 depth. The surface of tlie sea continued in this peaceful 

 state until, on the 7th of October, 1848, at the place of the 

 previous breach, a second terrible eruption of flames* ap- 

 peared, without any perceptible earthquake in the vicinity, 

 lasted for several days, and was visible at a distance of from 

 40 to 50 miles. The salse only emitted gases, but no solid 

 matters. When the flames had disappeared the sea-bottom 

 was found to be raised into a small sandy islet, which how- 

 ever soon disappeared again. More than 50 volcancitos 

 (cones similar to those of Turbaco) now surround the sub- 

 marine gas volcano of Galera Zamba, to a distance of from 

 18 to 23 miles. In a geological point of view we may cer- 

 tainly regard this as the principal seat of the volcanic ac- 

 tivity which strives to place itself in contact with the atmos- 

 phere, over the whole of the low country from Turbaco to 

 beyond the delta of the Rio Grande de la Magdalena. 



The uniformity of the phenomena which are presented in 

 the various stages of their activity, by the salses, mud vol- 

 canoes, and gas springs on the Italian peninsula, in the 

 Caucasus and in South America, is manifested in enormous 

 tracts of land in tlie Chinese empire. The art of man has 

 there from the most ancient periods known how to make use 

 of this treasure; nay, even led to the ingenious discovery 

 of the Chinese rope-boring, which has only of late become 

 known to Europeans. Borings of several thousand feet in 

 depth are produced by the most simple application of human 

 strength, or rather of the weight of man. I have elsewheref 

 treated in detail of this discovery, and also of the "fire 

 springs," Ho-tsing, and "fiery mountains," Ho-schan, of 

 Eastern Asia. They bore for water, brine springs, and in- 

 flammable gas, from the southwestern provinces, Yun-nan, 

 Kuang-si, and Szu-tschuan on the borders of Thibet, to the 



* Lettre de M. Joaquin Acost-a a M. Elie de Beaumont, in the 

 Comptes rendus de I' Acad, des Sciences, t. xxix., 1849, p. 530-534. 



t Humboldt, Asie Centrale, t. ii., p. 519-540; principally from ex- 

 tracts from Chinese works by Klaproth and Stanislas Julien. The 

 old Chinese rope-boring, which was repeatedly employed, and some- 

 times with advantage, in coal-pits in Belgium and Germany between 

 1830 and 1842, had been described (as Jobard has discovered) as early 

 as the 17th century, in the Relation of the Dutch embassador, Van 

 Hoorn ; but the most exact account of this method of boring the fire- 

 springs {Ho-tsirtg) is given by the French missionary, Imbert, who re- 

 sided so many years in Kia-ting-fu (see Annates de la Propagation de 

 la Foy, 1829, p. 369-381). 



