444 Dr. Tempest Anderson and Dr. J. S. Flett. 



definitely ascertained. For some honrs afterwards there were brilliant 

 lightnings and loud noises which we took for thunder. That night 

 there was a heavy thunderstorm over the north-end of Martinique, 

 and much of the lightning was atmospheric, but probably the eruption 

 had something to do with it, and the noises may have been in part of 

 volcanic origin. 



There can be no doubt that the eruption we witnessed was a 

 counterpart of that which destroyed St. Pierre. The mechanism of 

 these discharges is obscure, and many interesting problems are in- 

 volved. But we are convinced that the glowing avalanche consisted of 

 hot sand and gases — principally steam ; and when we passed the hill 

 in E.M.S. "Wear" a few days later, we had, by the kindness of the 

 captain, an excellent opportunity of making a close examination of the 

 shore from the bridge of the steamboat. The south-west side of the 

 hill along the course of the Eiviere Seche was covered with a thin 

 coating of freshly fallen fine grey ashes, which appeared to be thickest 

 in the stream valleys. The water of the rivers flowing down this part 

 of the hill was steaming hot. This was undoubtedly the material 

 emitted from the crater on the night of the eruption. There was no 

 lava. We saw no explosions of combustible gases, and nothing like a 

 sheet of flame. We were agreed that the scintillations in the cloud 

 were ordinary lightnings which shot from one part of its mass to 

 another, and partly also struck the sea beneath. 



The most peculiar feature of these eruptions is the avalanche of 

 incandescent sand and the great black cloud which accompanies it. 

 The preliminary stages of the eruption, which may occupy a few days 

 or only a few hours, consist of outbursts of steam, fine dust, and 

 stones, and the discharge of the crater lakes as torrents of water or of 

 mud. In them there is nothing unusual, but as soon as the throat of 

 the crater is thoroughly cleared, and the climax of the eruption is 

 reached, a mass of incandescent lava rises and wells over the lip of 

 the crater in the form of an avalanche of red-hot dust. It is a lava 

 blown to pieces by the expansion of the gases it contains. It rushes 

 down the slopes of the hill, carrying with it a terrific blast, which 

 mows down everything in its path. The mixture of dust and gas 

 behaves in many ways like a fluid. The exact chemical composition 

 of these gases remains unsettled. They apparently consist principally 

 of steam and sulphurous acid. There are many reasons which make 

 it unlikely that they contain much oxygen, and they do not support 

 respiration. 



After visiting Martinique we proceeded to Dominica, where Dr. 

 Flett visited the Soufriere at the south-end of the island, and the 

 famous Boiling Lake and Grand Soufriere. There have been few 

 signs of increased volcanic activity here or in St. Lucia during the 

 recent eruptions. Dr. Tempest Anderson spent some days in 



