SALSES. 207 



find nothing in thorn that could make mc at all doubtful now; 

 and the observation already referred to (from Parrot's Ke- 

 ports), that " the gas of the mud volcanoes of the peninsula 

 of Taninn in 1811 had the property of preventing combus- 

 tion, as a glowing chip was extinguished in the gas, and 

 even the ascending bubbles, a foot in diameter, could not be 

 ignited at the moment of their bursting," while in 1834 

 Gobel saw readily inflammable gas burning with a bluish 

 flame at the same place — leads me to believe that the ema- 

 nations undergo chemical changes in different stages. Very 

 recently Mitscherlich has, at my request, determined the 

 limits of inflammability of artificially prepared mixtures of 

 nitrogen and hydrogen gases. It appeared that mixtures of 

 one part of hydrogen gas and three parts of nitrogen gas 

 not only took fire from a light, but also continued to burn. 

 When the quantity of nitrogen gas was increased, so that the 

 mixture consisted of one part of hydrogen and three and a 

 half parts of nitrogen, it was still inflammable, but did not 

 continue burning. It was only with a mixture of one 'part of 



drogen gas, the quantitative amount of which we do not at present 

 know. Does the same carbonaceous schist that I saw farther west- 

 ward on the Rio Sinu, or marl and clay, lie below the Volcancitos ? 

 Does atmospheric air penetrate through narrow fissures into cavities 

 formed by water and become decomposed in contact with blackish 

 gray loam, as in the pits in the saline clay of Hallein and Berch- 

 tholdsgaden, where the chambers are filled with gases which extin- 

 guish lights ? or do the gases, streaming out tense and elastic, prevent 

 the penetration of atmospheric air ?" These questions were set down 

 by me in Turbaco 53 years ago. According to the most recent ob- 

 servations of M. Vauvert de Mean (1851), the inflammability of the 

 gas emitted has been completely retained. The traveler brought with 

 him samples of the water which fills the small orifice of the craters 

 of the Volcancitos. In this Boussingault found in the litre : common 

 salt, 6*59 gr. ; cai'bonate of soda, - 31; sulphate of soda, O20; and 

 also traces of borate of soda and iodine. In the mud which had fall- 

 en to the bottom, Ehrenberg, by a careful microscopic examination, 

 found no calcareous parts or scoriaceous matter, but quartz granules 

 mixed with micaceous lamina:, and many small crystalline prisms of 

 black Augite, such as often occurs in volcanic tufa ; no trace of Spon- 

 giolites or Polygastric Infusoria, and nothing to indicate the vicinity 

 of the sea, but on the contrary many remains of Dicotyledonous 

 plants and grasses, and sporangia of lichens, reminding one of the 

 constituents of the Moya of Pelileo. While C. Sainte-Claire, Deville, 

 and George Bornemann, in their beautiful analyses of the Macalube 

 di Terrapilata, found 099 of carbureted hydrogen in the gas emitted, 

 the gas which rises in the Agua Santa di Limosina, near Catanea, 

 gave them, like Turbaco formerly, 0*98 of nitrogen, without a trace 

 of oxva;cn (Comptes rendus de I Acad, des Sciences, t. xliii., 1856, p. 

 361 and 366). 



