760 JOSE MARIA ARREOLA 



March ii, 12, and ij. — Almost inactive. 



March 14. — At i A, m., a great eruption, with fire in the cloud and over- 

 flow of glowing scoriae on the flanks. It produced a rain of fine sand to the 

 east, in Tonila, and to the southwest in the Hacienda: de San Antonio, esti- 

 mated, at the latter place, at ten grams to the square meter. Inactive the 

 rest of the day. 



March 15-23. — Almost inactive. 



March 24.. — At 1:55?. '^v ^ maximum eruption, in six impulses, dur- 

 ing the period of thirty-five minutes (Fig. 8). At the beginning frequent 

 rumblings were heard, during some five or six minutes. The cloud directed 

 itself east-northeast ; and produced a rain of coarse sand in Tuxpan, Teca- 

 litlan, etc. 



March 25-ji. — Almost inactive. 



CONCLUSIONS. 



1. The volcano of Colima has been from time immemorial an 

 active volcano, the eruptions of which gain force, in some periods, 

 until they assume a violent character. 



2. The intervals between the periods of great activity, and 

 the duration of these periods, are irregular .... 



3. The characters of all the violent eruptions recorded in his- 

 tory are similar to those of the present time. The only notable 

 incident is the appearance of a secondary crater, to the north- 

 west of the principal, at the beginning of the 1869 period, which 

 functioned until 1872. 



4. From the examination of the flanks of the volcano and 

 from recent superficial observations, it is inferred that the volcano 

 has never thrown out lavas. All that lies upon the constituent 

 rock mass of the cone, and all lately ejected, are fragmentary 

 material — pebbles and sands of various grades of fineness, some 

 with marks of having been exposed to heat and to the emana- 

 tions from the crater. It appears, then, that they do not pro- 

 ceed from the internal reservoir. 



5. The reason that this volcano has never belched forth lava is 

 that its impulsive force has never been sufficient to overcome the 

 height — 3,960 meters above sea level. The lava rises to a level 

 lower than this in the crater, and only the hot scoriae, floating 

 upon its surface, overflow. 



6. The heavier products erupted fall upon the higher slopes 



