F. A. Perret — Lava Eruption of Stromholi. 451 



her the direct employment of a thermoelectric pyrometer was 

 prevented only by the heavy seas which made impossible a 

 sufficiently near approach to the stream flowing into the sea at 

 the Sciara's base. Any approach to the source itself was pre- 

 cluded by its position immediately under the crater. 



On the basis of the degree of incandescence. I estimated the 

 temperature at 1100(±)°C. — this being mentally compared 

 with the incandescence of lava whose temperature was meas- 

 ured, at Etna and Ivilauea. 



The solidified lava is a very dense, black basalt, which shows, 

 in an evidently vitreous ground mass, many small phenocrysts 

 of augite, few of olivine and none of feldspar. Its petro- 

 graphical characters and relations will be described later by 

 Washington in connection with other rocks of the Aeolian 

 islands, but it will be as well to put on record here its chemi- 

 cal composition as contrasted with those of other recent Strom- 

 boli basalts. 



A B C D 



SiO, .. 50 00 5055 50-83 51*05 



A1 2 3 13-99 16-58 16-66 15-09 



Fe 3 3 . 5-13 8-18 1-52 2-07 



FeO 9-10 6-64 6-88 



MgO 4-06 6'10 6-08 6-52 



CaO 10-81 11-45 10-99 1134 



]S'a,0 3-02 3-15 2-66 2-53 



K,0 2-87 3-16 2-05 2'02 



11,0 0-24 006 0-36 0-15 



Ti0 2 n.d. n.d. 0-81 0-83 



Zr0 3 .- -- n.d. n.d. n.d. none 



P,0 B .... 0-71 0-67 1-61 1-44 



S<) 3 trace n.d. n.d. 0-06 



Cr 2 3 n.d. n.d. n.d. 0-05 



MnO 0-42 n.d. 0-12 0*13 



100-35 99-90 100-33 100-12 



A. Basalt of 1S91. L. Ricciardi analyst. Ricco and Mer- 

 calli, Ann. Uff. Cent. Met. Ital., xi, Pt. Ill, p. 202, 1892. 



B. Basalt of 1894. F. Glaser analyst. A. Bergcat, Die 

 Aeolischen Inseln, p. 44, 1899. 



C. Basalt of August, 1914. II. S. Washington, analyst. 



D. Basalt of November, 1915. H. B. Washington, analyst. 



Although the two earlier analyses, especially that of Ricci- 

 ardi, are not very satisfactory, it is evident that at Stromboli, 

 as at Vesuvius, Etna and many other volcanoes, the composi- 

 tion of the lavas of the basaltic phase has remained very uni- 

 form. As Bergeat points out,* the chemical composition of 

 *A. Bergeat, Die Aeolischen Inseln, p. 45, 1899. 



