528 
DK8. T. ANDERROX AND J. R. FI.ETT OX THE ERUPTIOXR OF THE 
of the explosion. According to the investigations of Lord liAYLErcH, quoted in the 
Krakatoa repoi't to the Loyal Society,"^ it diminishes in proportion to the square of 
the distance from the focus, and Lieutenant-General Strachey, R.E., calculates that 
the initial velocity of the air waves generated by that eruption was about 713 miles 
an hour. The gi'eat explosion at the Soufriere should, in consequence, have affected 
the barometiic column in Barbados in less than 10 minutes. So far as we know at 
present, the eruption in St. A^incent on May 18th did not leave any record on the 
barograms, either in Barbados or in Martinique. 
8 10 M 2 4 6 8 10 XII 2 4 6 8 10 Pvi^TT 
[VI I 3 O A. 
Mhy ZoVr Id o Z . 
Ndilil hMEELA 
— 
li 
—-^- 1-4— 
-M—-j 
1!L 
n i I I I i I I I I I I 
A(a Y O a /D >Z. 2. 4 8 1° tZ 
J-uuY 3 , 13 02- 
Aug.ust 
Flo. 3.—Biirograpliic tracings, showing the air waves generated hy the eruptions of Montague Pelee. 
Taken in the station of the American A\Mather Bureau, Kozeair, Dominica. 
The form of the Yvave tmcing is precisely that given Ity sudden and violent 
explosions. We have olTained from Mr. Porter, of Bozeau, in Dominica, photographic 
copies of the barograms yielded by his j'ecording barometer at that station (through 
the kindness of Mr. Hobbs, of the Amei ican AVeather Bureau, St. Kitts). (Fig- 3.) 
The characteristics of the waves have already been emphasised hy Professor Lacroix 
* “The Eruption of Krakatoa,” ‘ Boyal Rociety’s Report,’ p. 64, 1888. 
