and the Elastic Limit of Lama. 



289 



no sensible error is involved in this assumption. The average 



2k 

 value of — obtained was 2*86 centimeters. To reduce the 



diagram to any desired unit, c, it is only necessary to redraw 



it to a scale in which — - — is treated as unity. The value of c 



2-86 J 



which I happened to find convenient was 4 cm . I drew both 

 sides of Fusiyama to the same soale to which I had plotted the 

 equation of the solid of maximum stability and give the plots 

 below. I treated Kumagatake in the same way, getting the 

 value of the natural unit in Professor Milne's diagram as 2'61 cm . 

 In fig. 1 may be seen the theoretical locus and Professor 

 Milne's outlines of these cones reduced as described. They 

 are drawn to the same axial line but to different bases, so that 

 for purposes of exact comparison a tracing of one should be 

 made and shifted vertically until it more or less nearly coin- 

 cides with the other. If this is done, a similarity will be 

 revealed between the results of theory and the facts which 

 seems to admit of but one explanation. 



Figure 1. — Theoretical curve and outlines of actual volcanoes. The comparison 

 is to be made by vertical transposition. I, is y= — - — ; II, Milne's outline of 



Fusiyama; III, Milne's outline of Kumagatake; IV, Shasta, enlarged from 

 Taber's stereoscopic view from north side, No. 1542 ; V, Hood from the Dalles, 

 enlarged from Watkins' New Boudoir Series, D. 61; VI, Popocatapet'l enlarged 



2 k 

 from A. Briguet's photos of Aqueduct of Tomacoco Mill, No. 19 ; c, the unit or — . 



I may mention that the slopes as given by Professor Milne 

 are reproduced as accurately as it is practicable to draw them 

 to an altered scale, and that the natural units obtained as 

 stated were used without any correction or adjustment. That 

 for Fusiyama might be changed a trifle, for, according to my 

 computations, Professor Milne has not taken the axis quite at 



