Scientific Results of the Katmai Expeditions of the 

 National Geographic Society. 



VI. THE WATER SOLUBLE SALT CONTENT, THE FER- 

 ROUS IRON CONTENT AND THE ACIDITY OF 

 KATMAI VOLCANIC ASH. 



J. W. Shipley, 

 Chemist of the 1917 Expedition. 



Certain samples of Katmai volcanic ash collected by Dr. 

 R. F. Griggs in 1916 were found by him not to support the 

 growth of plants, but on the contrary apparently to have a 

 toxic effect upon germinated seedlings. Qualitative tests made 

 by the author upon these samples indicated the presence of 

 ferrous sulphate together with a decided acidity in the water 

 extract. During the expedition of 1917 other samples of ash 

 were collected from deposits upon which vegetation had secured 

 a more or less precarious hold, and in which field observations 

 showed acidity in conjunction with the presence of ferrous iron. 

 These samples were analyzed with the object of ascertaining 

 whether the acidity and ferrous iron content was sufficient 

 to account for the apparent sterility. 



Sample No. 1. Stream deposited ash from near Katmai Church 

 at the mouth of Katmai River, collected in 1916. Sample 33, 

 Vegetation Station No. 102. Wheat germinated, but the seedlings 

 quickly became malformed and never appeared above the surface. 

 For determination of nitrogen content, see page 218. 



Sample No. 2. Katmai Mud Flow on Katmai Volcano, collected in 

 1916. By itself it was toxic to wheat, but this toxicity was removed 

 when it was mixed with coarse sand. 



Sample No. 3. Katmai Mud Flow, collected in 1917. 



Sample No. 4. Pillar Mountain Station, Kodiak Island. Vegeta- 

 tion Station No. 1-1. Collected in 1917. Plants not growing. 



Sample No. 5. Katmai River mud, deposit above Camp II. 

 Seedling grass growing. For nitrogen content see page 218. 



Sample No. 6. Similar to No. 5, and close to it, but seedling grass 

 had died. For nitrogen content see page 218. 



The analysis was carried out on 100 gram samples of the 

 air dried ash. This amount of each sample was placed on a 

 filter paper in a funnel and lixiviated with successive portions 



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