282 



BECKER 



diameter, would strike like bullets on a target of which the bull's 

 eye represents the orifice of the spray. The distribution of the 

 mass as a whole would then be given by the well known proba- 

 bility curve, but the geometrical configuration of the aggrega- 

 tion would be somewhat different. Takingr the constant of the 

 probability curve as equal to -^71 so that the maximum ordinate, 

 zf , becomes unity, the equation of that curve is 



w = c~'"". 

 For the solid figure representing the driblet cone, it is easy to 

 see that if z is the vertical ordinate i-rdr- z = zvdr or 



z = . e—"' . 



2-r 



This I take to be the most natural form of a driblet cone. 

 If perfect, it would be a slender spine reaching an infinite 

 height though of finite volume, but wind or seismic jars would 

 prevent its growing very high, even if the molten spray spurted 

 to indefinite heights and the orifice were of infinitissimal diam- 

 eter. Hence the column in nature would be truncated and would 

 doubtless be surrounded by a talus. It is so represented in fig. 

 25, while one of Dana's figures is reproduced in 2a. 



TiiK CATiitURAL ; Dkiiu.etconk, 181J4. 

 Fig. la. 



It is imaginable that the famous spine of Pelee might have 

 been formed in this way, but llie evidence points rather to Mr. 

 Lacroix' hypothesis of extrusion, something as a lead rod is 

 forced out of a cvlinder by pressure. 



