56 Perret — Representation of Volcanic Phenomena. 



on a large scale under actual working conditions that the value 

 of a new process can be determined, and, to this end, the writer 

 is prepared to furnish these charts gratis, in several languages, 

 to investigators, and will endeavor to keep a supply on hand 

 at all observatories or stations at volcanic centers, or with the 

 local authorities, for free distribution to visiting scientists. 



Believing that a special punishment is reserved for those 

 who lightly or unworthily bring forward any new thing, the 

 writer has labored to produce a method which should include 

 all essentials without undue complication and without the 

 sacrifice of workability, bearing constantly in mind the not 

 infrequent moments of his own observations and seeking the 

 counsel of practical fellow workers, for whose kindly aid he is 

 duly grateful. 



Posillipo, Naples, October, 1913. 



