138 Washington — /Submarine Eruptions of 1831 and 1891, 





I 



II 



III 



IV 



la 



SiO„ 



48-97 



49-24 



51-87* 



61-08 



816 



A1 9 3 



16-37 



19-06 



15-30 



17-37 



160 



Fe 8 O s 



1-33 



1-77 







7-77 



008 



FeO 



8-56 



10-33 



11-40 







119 



MgO 



6-22 



5-00 



8-66 



4-02 



156 



CaO 



7'49 



8-75 



7*46 



1*46 



134 



Na 2 



4-09 



3-89 



3-90 



2-85 



066 



K 2 



1-72 



1-19 



0-85 



1-82 



•018 



H 2 + 

 H 2 0- 



0-38 | 

 0-08 j 



0-63 







1'63-f 





Ti0 2 



3-95 











1-45* 



•049 



P.O. 



1-04 















•007 



MnO 



0-06 







0-60 



0-62 



001 



MO 



0*08 















•001 





100-34 



99-86 



100-04 



100-09 





* "Kieselerde mit Titansaiire. *' 



f " H 2 + CI + H 2 S " = loss on ignition. 



I. Andose (feldspar-basalt scoria). Graham Island. Wash- 

 ington analyst. 



II. Andose (feldspar-basalt scoria). Graham Island. H. Foerst- 

 ner analyst. Tsch. Min. Petr. Mitth., vol. v, p. 391, 1883. 



III. Black basaltic scoria. Graham Island. H. Abich analyst. 

 Vulk. Ersch., p. 74, 1841. 



IV. Light gray trachytic pumice. Shore near Sciacca, floated 

 from Graham Island. H. Abich, analyst. Vulk. Ersch., Table 

 III, No. 3, 1841. 



la. Molecular ratios of I. 



The analysis of basalt by Abich (II), made by fusion with 

 barium carbonate, is very satisfactory, considering its date and 

 the crude methods and reagents available at the time. It 

 shows the broad chemical characters of the rock quite clearly, 

 except the large amount of titanium, though the recognition 

 of the presence of this constituent is noteworthy and is indic- 

 ative of Abich' s acumen and the accuracy of his analytical 

 work. Analysis IV will be discussed later. 



Classification. — Analysis I yields the following norm : 



Or 



10-01 ) 



Ab 



34-58 [ 



An 



21-13 ) 



Di 



7-91 I 

 14-44 f 



01 



Mt 



1-86 | 



11 



7-45 C 



Ap 



2-35 



Rest 0-60 



22-35 j 



9-3i r 



2-35 ) 



65-72 



34-01 



Sal 



1-93 



Fern 

 F 



L = °° 

 K 2 Q+Na 2 Q 

 . CaO' 



= 0-90 



KO 



100*3' 



Na 2 



= 0-27 



Class II 

 dosalane. 



Order 5 

 gerinanare. 

 Rang 3, 

 andase. 



Subrang 4 y 

 andose. 



