92 MICHIGAN ACADEMY OF SCIENCE. 



and second usin^- Tlic diameter of the <irains as determined bv aspira- 

 tion. These weij^hed lols of soil were then subjected to the action of 

 a standard solvent for about ten days, when the losses were determined. 

 Theoretically the losses should be propoit ioiial to the total surfaces of 

 the lots of soil. The losses were jtloited as were also the surfaces as 

 based ujton the diameter determined by the two methods. 



There was no apparent relaticm between the losses and the surfaces 

 obtained by usinj;- the diameters obtained by the old method, while 

 the curve of losses was not far fi-om parallel to the curve of surfaces 

 obtained by the as}»irati(ui method. 



The results obtained by mixing- a tine j-rade of sand with a coarse 

 grade, vtiryinji in proportions, do not give results that agree with the 

 theoretical value. 



THE LIFE HISTORY OF A A^OLPAXir ISLAND. 



DR. A. B. LYONS. DETROIT. 



The publication rectmtly of an imjiortant paper l)y Prof. C. H. Hitch- 

 cock on the Geology of Oahu renders timely a discussion of the general 

 subject of the life history of a volcanic island. Nowhere in the world 

 can this subject be studied to better advantage than in the Hawaiian 

 Islands. Every stage, unless it be the initial one. which necessarily 

 must be unobserved, is here illustrated. 



According to ancient Hawaiian tradition, Pele, the goddess of the 

 volcano, dwelt first in the most northerly islands of the group. From 

 time to time she moved hei- residence southward, occu]»ying in succes- 

 sion Kauai, Oahu, \lolokai and Maui, and finally taking up her abode 

 on Hawaii. This is simply a mythological version of the scientific state- 

 ment that volcanic action in the Hawaiian group has built up the 

 islands in succession beginning at the most northei'ly, being confined 

 today, as you all know, to the most southerly. 



Hawaii, then, represents a volcanic island still in its period of vigor- 

 ous growth. ^launa Loa, its active volcano, consists of a regular dome, 

 the even curve of its outline as seen in ]irofile almost unbroken by 

 subsidiary cones, its slopes not yet scored in any degree by erosion. 

 The rain which falls copiously on some ])ortions of its slope is absorbed 

 as by a gigantic sponge. Ten or fifteen inches of rain in a day, in the 

 Olaa rejiion is not an uncommon record, vet the word freshet conveys' 

 no meaning to the Kamaaina. The water from such a down pour, where 

 it falls on pahoehoe lava will How down the slope of course, in a 

 broad sheet (there are no water courses toi- it t(t follow), but even on 

 pahoehoe it can go but a very short distance b(4"ore it is sucked into 

 the ]K)res of the vesiculai- lava. If it falls on aa, it disappears at once. 



Manna Kea, the twin peak, icpresents the next stage in the life 

 history of a volcano. The cone has been com])leted, its surface studded 

 with nnmerctus parasitic cones, characteristic of the later stages of 

 volcanic activity. The cone as a whole is steei)er than that of Manna 



