Volcanic Disturbances in West Indies 299 



prior existence of sulphates in the mat- 

 ter ejected from Soufriere, for while 

 there may have been such near the sur- 

 face, resulting from fumarolic or sol- 

 fataric action, the temperature at which 

 the sulphide came in contact with air 

 must have been sufficiently high to effect 

 an appreciable conversion not only to 

 the condition of sulphurous acid, but 

 to that of sulphuric acid as well. 



In making further analyses chemists 

 should be particular to ascertain the con- 

 dition of sulphur in these ejecta, and 

 not be content to report it simply as 

 SO ;l without further comment. Work 

 of this kind is worth doing well, or it 

 were better left undone. 



It may here be said that in the anal- 

 yses showing much sulphide the values 

 given for the oxides of iron are only 

 approximate. The exact error due to 

 the effect of a more or less soluble sul- 

 phide like pyrrhotite it is impossible to 

 gauge, though, of course, there is no 

 difficult}' in correctly ascertaining the 

 total amount of iron, which serves as 

 the basis for calculating the oxides and 

 sulphides. 



Earlier in this paper I alluded to one 

 disagreement between the analyses re- 

 ported by the chemists of the Geological 

 Survey and that by Dr Pollard in Nature 

 (Diller's No. 5). This relates to the 



presence of nickel and cobalt. Either 

 we of the Survey have overlooked traces 

 of nickel because of some inherent de- 

 fect in our method or Dr Pollard has 

 counted as nickel something which was 

 not that element. I may say, as the 

 result of our experience of many years, 

 that such amounts of nickel as were re- 

 ported by Dr Pollard are rarely met 

 with except in peridotitic rocks, and 

 that hundreds of analyses of almost 

 every other kind have been made with- 

 out finding such a large amount. 



Dr Porter, in Nature, p. 131, men- 

 tions with some reserve the finding of 

 a trace of copper in his specimens of 

 dust from Barbados. This observation 

 I believe to be quite correct. I also 

 found it in the three specimens from 

 Pelee, just as we find it in nearly every 

 rock analysis that is made in the Survey 

 laboratory. We seldom report it be- 

 cause of the opportunities usually pres- 

 ent for its introduction from outside ; 

 but my personal belief is that it is as 

 universally distributed through rocks as 

 any .one of the other metals, though of 

 course in very small amounts. 



Some of the points referred to in this 

 paper may with advantage be dwelt 

 upon at greater length in a future pub- 

 lication, when further data are available 

 for examination and discussion. 



REPORTS OF VESSELS AS TO THE RANGE 

 OF VOLCANIC DUST 



Compiled by James Page, U. S. Hydrographic Office 



FROM the log of the barque Beech- 

 wocd, Dennison, master ; Sala- 

 verry to New York : 

 ' May 8, latitude 13 22' N., longi- 

 < tude 49 50' W. (Mont Pelee W. by N., 

 660 miles), wind E. N. E., force 4; sky 

 overcast and tinted a buff color ; fine 

 gray dust began to fall at noon. 



"May 9, latitude 14 46' N., longi- 

 tude 51 ° 27' W. (Mont Pelee W., 540 

 miles), wind E. N. E., force 4; sky 

 cloudy ; dust ceased falling about noon. 



' ' On my reference to a chapter in the 

 directory called 'An account of the fine 

 dust which often falls on vessels in the 

 Atlantic, and which comes from the 



