394 



SCIENCE. 



[Vol. VI., No. 143. 



theories, attributing the earthquake to the tension 

 of vapor of water in the subjacent strata. The 

 valley of Zafarraya, indicated above as the prob- 

 able focus, is a locality where much water gathers 

 and easily penetrates beneath the surface, and to 

 the vapor of high tension produced from the 

 water here collected in deep-lying strata are attri- 

 buted the forces which gave rise to the present 

 earthquake. It is assumed that in general the 

 lines of seismic propagation, following crevices in 

 the strata beneath the surface, will accord with 

 the direction of the surface water courses. On this 

 idea, the principal radiant lines from Zafarraya 

 were along the rivers Marchau and Genii; a view 

 which is regarded as confirmed by the phenomena 

 in the Sierras Tejeda, Marchamonas, and Eumedio, 

 where large crevasses occurred parallel to the 



will be awaited with interest, and will doubtless 

 contain valuable additions to the science of seis- 

 mology. 



The report is signed by Manuel Fernandez de 

 Castro, Juan Pablo Lasala, Daniel de Cortazar, and 

 Joaquin Gonzalo y Tarin. 



THE NORDENFELT SUBMARINE BOAT.' 



Just before leaving Denmark for the south, the 

 Prince of V\^ales, with the King and Queen of Den- 

 mark and the Czarina, witnessed off Landskrona, 

 a town on the Swedish coast, an interesting and 

 successful trial of the new submarine boat, which 

 has been built at Stockholm upon the plans of 

 Mr. Nordenfelt, the inventor of the machine gun 

 so extensively used in modern warfare. Ever 



THE TRIAL OP THE >ORDENFKLT SUBMAKINJfi BOAT AT LANDSKKONA, SWEDEN. 



direction here indicated. In the province of Mal- 

 aga the principal seismic effects were found in 

 the vicinity of Periana, adjoining the district 

 designated as the focus, but on the other side of 

 the sierra, which separates the two provinces, and 

 here the principal radiant line followed the course 

 of the river Velez. 



Theoretical considerations suggesting that the 

 area affected should approximate in form to an 

 eUipse, this is found to agree with the observa- 

 tions ; but the data at hand do not suffice for any 

 exact determination of the direction and velocity 

 of the movment, nor of the depth of the focus. 



In conclusion, then, the report fixes upon 

 Zafarraya as the focus of this earthquake, and 

 suggests a probable cause for it in the subterranean 

 waters gathered there ; but more exact results are 

 yet wanting, and may very likely remain so, even 

 when the fuller report is issued. This, however, 



since the American civil war, naval engineers have 

 been striving to solve the problem of submarine 

 navigation, but until now with very little success. 

 Mr. Nordenfelt's invention, however, appears to 

 fulfill the numerous requirements necessary for 

 overcoming the difficulties and dangers of main- 

 taining, driving and directing a boat beneath the 

 water. The boat is built of steel, and is cigar- 

 shaped, with a glass conning-tower in the centre, 

 from which the commander can keep a look-out. 

 This dome is protected by a strong iron cover. 

 There are three engines, one to work the screw in 

 the stern which propels the vessel, and two to 

 work the propellers on either side, which, when 

 set in motion, compel the boat to sink, and main- 

 tain her at a certain depth beneath the surface. 

 When it is wished to sink the boat, enough sea- 

 water is taken in to reduce the buoyancy till the 

 iFrom the London Graphic. 



