GEOPHYSICAL LABORATORY. 139 



plished. No moving pictures were attempted, under such circum- 

 stances, although the complete apparatus was carried. Observations 

 of importance, too numerous for mention here, were made during the 

 stay within the crater. 



A project has been set on foot to utihze the heat of the Solfatara by 

 the generation of electric power for industrial purposes and I have 

 been appealed to for advice and the making of some preliminary 

 soundings. I have consented the more readily as the work will even- 

 tually involve deep borings which can not fail to increase our knowledge 

 of conditions in the hidden portions of this volcanic vent. I have so 

 far made borings to a depth of 6 meters. These tend to show the cor- 

 rectness of the h>T)othesis that the crater formerly contained a lake of 

 boiling mud. The most striking thing revealed by these experiments 

 is the extension of this stratum of wet clay at 100° C. over practically 

 the entire area of the present floor at a depth of 1 meter. Even under 

 the portions covered with vegetation the same temperature obtains 

 and a new and powerful fumarole may be created at will in any place 

 whatever. By placing a pipe so as to provide a conduit not destroyable 

 by collapse of its walls, I have made fumaroles which are permanent. 

 A syndicate for carrying out this project is in process of formation. 



Laboratory work. — Much laboratory work has been done. Appa- 

 ratus for recording upon wax cylinders the subterranean sounds of 

 volcanoes has been brought almost to perfection. It was found that 

 the commercial cylinders were unsuitable for this delicate work, and 

 the Columbia Graphophone Company was appealed to to make up a 

 quantity of the old, pure wax type. They have kindly done this, the 

 Geophysical Laboratory has purchased them, and they have arrived 

 here. The microphone itself has now been greatly improved, and a 

 perfect little portable field outfit weighing less than a pound has been 

 evolved. Several electrical and other instruments have been added to 

 the laboratory equipment, and experiments initiated along various 

 lines, such as the condensation of water vapor through nucleation, 

 magnetic concentrating lens, volcano experiment models, etc. A 

 dark-room outfit has been added, as mentioned below. 



Photography. — ^Existing conditions have greatly affected this branch 

 of the work, not only directly by the difficulty of obtaining good 

 material and its increased cost, but by the necessity of personally 

 losing time in printing, washing, etc., which might be employed more 

 profitably. The closing of the studio of G. Sommer & Son and the 

 removal of the family to Rome has been compensated only partially by 

 the instalment of a little dark-room outfit here, which permits the devel- 

 opment of negatives and the making of prints but not enlargements. 



Publicity.- — A popular lecture on "The study of the world's vol- 

 canoes, and what it reveals" was given at Naples for the benefit of the 

 Anglo-American Church. The lecture was illustrated with colored 



