J. D. Dana — History of the Changes in Kilauea. 215 



III. THE OKDINAKY WOKK OF KILAUEA. 



By the ordinary work of Kilauea is here meant the work which 

 is carried on between epochs of eruption. A large part of it 

 is the living work of the volcano, the regular daily action, never 

 permanently ceasing except with the decline and extinction or 

 withdrawal of the tires. The deep-reaching conduit of lavas, 

 which is the source of the heat and center of this living activity, 

 owes a large part of its power to act the volcano, and make a 

 volcanic mountain, to the presence of something besides heat 

 and rocks. Vapors are ever rising and escaping from the 

 conduit, and though lazy in the clouds above where the work is 

 done, they carry on nearly all the ordinary action of a crater, 

 even that of greatest brilliancy and loftiest fiery projection as 

 well as the gentler play of the fires. But these vapors have 

 not produced the great eruptions in Kilauea since 1822 ; they 

 occasion only its quiet or lively activity in periods of regular 

 work between eruptions. I add also, lest I be misunderstood, 

 that the vapors are bad for fuel, as they tend to put the fires 

 out, but good for work. 



There is another source of work, perhaps a perpetual source 

 during the active life of a volcano as it is a perpetual source of 

 heat, namely, the ascensive force of the conduit lavas. But, 

 unlike the vapors, it is an invisible agency, slow in its irresistible 

 movements. What are its limitations, and what its source still 

 remain undetermined. 



The other agencies concerned in the ordinary work have 

 only occasional effects. They include heat in work outside of 

 the conduit, and hydrostatic and other working methods of 

 gravitational pressure.* 



Tabulating the agencies, they are as follows : 



A. The vapors. 



B. The ascensive force of the conduit lavas. 



C. Heat, displacing, disrupting, fusing. 



D. Hydrostatic, and other gravitational pressure. 



All these agencies do their work around the lava conduit, or 

 its branches, as their central source of energy. Unlike non-vol- 



* The following account of Kilauea in December, 1874, was omitted from page 

 94 of vol. xxxiv. Tt is from a brief note by Mr. J. W. Nichols, of the British 

 Transit of Venus Expedition of 1874. published in the Proceedings of the 

 Edinburgh Ik^al Society for 1875-6, pp. 113-17. A low cone around Hale- 

 ma'uma'u about 70 feet high ; diameters of the basin \ m. and Jm.; within it, four 

 lava lakes, the largest 200 yds. in length ; in the largest, 7 to 8 fountains of 

 white-hot lava playing to a height of 30 to 40 feet', one of them sometimes stop- 

 ping, and then commencing in another part of the lake; the fountains in every 

 case playing around the edges of the lake; lava of largest lake about 50 feet be- 

 low the brim ; one of the smaller lakes brim full of lava when in the others the 

 lava surface was 30 or 40 feet below the brim; in one, a single fountain bursting 

 from a cavern in its side. The summit crater is stated to have been in action 

 about a month before the visit. 



