Reviews — The Water of Volcanoes. 175 



The method of indicating fossil localities in Appendix I should be 

 specially noted. By means of this, and on consulting the 6 in. maps 

 preserved in the Survey Office, the exact locality of any specimen 

 may be ascertained. We may hope that this admirable example may 

 frequently be followed by others, for nothing is more annoying than 

 to find a vague locality given for an important fossil. 



In congratulating all the authors of the memoir upon its matter, it 

 may be remarked that while full credit is given to previous workers 

 in the district for what they have done, the mistakes which they 

 have made are touched upon so lightly that they can usually be detected 

 only by consulting the original papers in which they appear. 



J. E. M. 

 II. — The Watkr of Volcanoes. 



IN the Geological Magazine for 1911 the present writer reviewed 

 a very striking book entitled Recherches sur V exhalaison volcanique, 

 written by Albert Brun of Geneva. 1 Brun's claim to have banished 

 water-vapour from among true volcanic emanations has now been 

 critically tested by Day & Shepherd 2 in its application to Kilauea, 

 and has been satisfactorily disposed of. Brun has not laboured in 

 vain, however, even apart from the many interesting side-issues 

 which he has raised. One feels, on reading the account given hy 

 Day & Shepherd of their experiences, that the long-accepted belief 

 in the importance of volcanic waters was in urgent need of direct 

 confirmation. No experimenters could have entered upon the task 

 with a greater prestige, and the result obtained will doubtless carry 

 conviction. Those who imagine that the water of volcanic activity 

 is a self-evident fact will be surprised to read that, although Day and 

 Shepherd undertook their study of Kilauea on May 1, 1912, and 

 waited till May 28 before an opportunity of collecting the gases at 

 last arose, they were even then caught quite unprepared for the 

 Avater which collected in their tubes ; so much so that they had actually 

 no apparatus ready at hand to estimate the proportion of the water 

 to the other volatile matter discharged by the lava ! Moreover, it 

 will be remembered that Lowthian Green, who as a resident in the 

 Hawaiian Isles enjoyed exceptional opportunities of observation, never 

 subscribed to the prevalent aqueous theory of volcanoes. 



Green's difficulties, it may be recalled, originated in his regarding 

 the intensity of the great white cloud of the volcano as a measure of 

 the vapours discharged. Where Green saw no cloud, he thought 

 that but very little vapour was liberated. But Day & Shepherd 

 prove that the cloud consists essentially of finely divided sulphur. 

 Where the vapours are released into the atmosphere direct from the 

 molten lava, they burn, and their products are invisible. It is only, 

 where cooled down by passage through fissures of the shattered floor 

 around the lava-lake, that the vapours yield- the characteristic white 

 cloud. 



Brim's observation that the cloud consists of solid particles thus 

 remains unchallenged. Brun noticed that the cloud when present 



1 See Geol. Mag., 1911, pp. 268, 311. 



2 A. L. Day & E. S. Shepherd, " Water and Volcanic Activity " : Bull. Geol. 

 Soc. Am., vol. xxiv, p. 573, 1913. 



