ToL. I. No. H. 



THE AGUICULTUllAL NEWS. 



217 



VOLCANIC DUST. 



FURTHER FALL AT J:.U!I'.AI)()S. 



]'>iinng the night of thf 1.5th. to thf Kith, instant 

 the SoutVit'iv at 8t. Vincent was in vioU.'nt eni))tion, 

 ■nnd iicconling to the brief telegia)iliie ir|iort to lianil, 

 .a heavy I'all of stones, aslies, etc., was cxjieiienced at 

 Georgetown and other jiarts of the ishmd. New.s li.ns 

 iilso been received of a tiiist .shcjwer at Castries, 

 .St. Lucia. Doubtle.ss fuller accounts of the course of 

 events in these islands will be .-ivailable after the 

 receijjt of to-day '.s mails. 



AtBarbados the weather during the 14th. and 1.5th. 

 had been sufficiently abnormal to cause at aii}' rate 

 one observer to take careful note of the clouds, wind, 

 teinj)erature and barometric readings. The morning 

 of Thursday the Kith, was noteworthy for the deep, 

 .slaty-blue cloud which, with a sharply defined lower edge, 

 advanced towards the island fi-oui the south-west. 'J'u 

 the north, the .sky was blue, with a few normal <-umu- 

 lus clouds. These as the}' passed in front of the 

 advancing dust-cloud, lost their whiteness and became 

 of an ash^'-grey colour. 



The sun was distinctlj' visible for only a lew 

 hours in the early morning. tiradually the cloud 

 jjassed in front. For some time the sun's di.sc was 

 seen shining through with a curious greenish tint, but 

 by about 10 a.m. it had practically disapix-'ared. At 

 intervals its position could be surmised, owing ajijj.-ir- 

 cntly to the dust-cl >ud being less dense in certain 

 places. 



In the south of the island dust began fdling 

 about 9 a.m. It was at first distinctly moist, and each 

 'drop' of dust consisted of a large number of line 

 particles which seattereil as they fell. 



We are indebted to Mr. R.'Radclyft'e Hall, B.A., 

 Acting- Professor of Chemistry at Bardados, for the 

 following particulars relative to the fall: — 



' Samples were collected at the Covernment 

 Laboi'atory in Bridgetown from 9 a.m. to 11 a.m., 

 from 11 a.m. to 1 p.m. and from 1 p.m. to o p.m. : the 

 blowing about of the dust by the breeze in the earlier 

 hours of the morning of the 17fch. ])revented the last 

 .sample, collected between o ji.m. on the Kith. .-11111 

 S a.m., on the 17th. being of any statistical value : tlie 

 rate ot fall was as follows : — 



October Ki. 



From 9 a.m. to 11 a.m. at the rate of '4^ tons 

 per acre. 



From 11 a.m. to 1 p.m. at the rate of 210 tons 

 per acre. 



Frou] 1 p.m tij o 11. m. at the rate of i:-!4 tons 

 jier acre. 



Total from 9 a.m. to S p.m. at the rate of :y.'>2 tons 

 per acie. 



I also collected two sam])les at ' Rosebank,' 

 Hastings, about two miles south-east of Bridgetown 

 ■where the fall was : — 



From 8.45 a.m. to 4 p.m. on Kith, at the rate of 

 4'59 tons per acre. 



From 4 p.m. on IGth. to 7 a.m. on 17th. at the rate 

 •of "20 tons i^cr acre. 



Of this -20 I estimate about 13 tons per acre ii.ul 

 fallen by .5.:iO ]).m. on the Kith. 



'These figures suggest that the tali at Hastings 

 was heavier than that in the neighbourhood of the 

 Government Laboi-ator^-. I had previously formed 

 the idea that the clouil was heavier towards its 

 south-wester)}' side and it seemed to me that it was 

 d.arker at Hastings than further inland and towards 

 the city, in fact we ajipear to lia\e obtained in this 

 case rather the " tail end" of the dust storm : the 

 coarser jiarticles may have travelled in a more southerly 

 direction than the previous one of May 7 and then 

 have fallen in the sea to the .south cast of Barba<los. 



If this were so, it would account for the fall begin- 

 ning so long, nearly hours, after the eruption, and we 

 should also expect to find that the fall was heavier 

 on the south easterly si<le of the islantl.' 



Mr. Hall adds:— 



' The noi.se caused by the eruption was sufficiently 

 marked to wake me at alxjut 2.80 on the morning of 

 the IGth. and while trying to locate the cause of my 

 awakening I noticed a distinct jarring pulsation of my 

 pillows : 1 got up and went to a western window and 

 then I heard a continuous dull lumble or series of 

 I'apidly following explosions, in a direction abou.t 

 W.N.W. of Hastings Rocks; I listened to this till 

 8 o'clock before going to sleep again. In the morning 

 I first noticed a heavy dark blue-black cloud all over 

 the horizon from about W.S.W. to N.W. and reaching 

 up about 30 ', while all the sky seemed shrouded in a 

 light brownish veil : by 7 a.m. the sun was shining 

 through this brown veil with a pale greenish light and 

 by 9 a.m. the dust had began to fall. At first I thought 

 the particles were very lai-ge and heavy but found that 

 on touch they crumbled to a fine impalpable ])owder, 

 so apparently they fell through a little rain or mist. 



'It would ap])ear at present that we may expect 

 this ])resent fall to have a slightly higher fertilizing 

 power than the last, since its valuable constituents 

 can become more rapi<lly available owing to the finer 

 texture of the particles.' The dust has been submit- 

 ted to a ]3reliminary microscopic examination by 

 Di-. Longfield Smith who re}Kirts : — 



' I have exa'.iiined the \olcanic dust which fell here 

 on October 10, 1902, and find it to be of much finer 

 texture than that which fell between May 7 and S, all 

 the grains being less than 1 millimeter diameter, while 

 77.S7 percent, of the dust fi-om the former eruption 

 of the Soufriere was coarser than 1 millimeter. 



' I collectedilust at " Nonjjareil", Hastings, every 

 hour fnmi 9.15 till 2.15 and then from 2.15 till 8.45, 

 ;ind found very little differenct' in texture or compcj- 

 sition between the successive samples. 



' The particles consist chiefly of minute fragments 

 of felspai- -^N'ith a little volcanic glass, some ferro- 

 magnesian minerals and a very little magnetite. 



' The dust differs therefore considerably in compo- 

 sition from that which fi'll on Jlay 7 and S, which 

 consisted largely of ferro-magne.sian minerals and 

 contained a considerable amount of magnetite. 



' On this account the dust is likely to prove of 

 greater fertilizing value than that of May 7 and 8.' 



