186 PROCEEDINGS OP THE ACADEMY OP [1884. 



In the suburbs of Philadelphia, some dust was collected by 

 Mr. Joseph Wharton,^ this winter, from melted snow, and from 

 the presence in it of certain rounded and filamentous glass par- 

 ticles supposed by him to be volcanic. Some of it had been 

 submitted by him to the speaker for examination. It appeared 

 to be composed of particles of quartz, coal, cinders, vegetable 

 matter, etc., among which are certain glassy hairs and rounded 

 globules. These bear no resemblance to the angular glass frag- 

 ments composing the Krakatoa dust, which is remarkably free 

 from either filaments or globules ; and the supposed volcanic 

 glass particles in the Philadelphia dust are most probably of local 

 origin — from blast-furnaces, foundries, or the like. 



Accompanying the specimens of dust from Krakatoa, were 

 extracts from the log of the bark, which present several points 

 of interest. A point of special importance is the record of a 

 sudden barometric fluctuation, due to a great atmospheric wave, 

 which, starting from the volcano at the time of the eruption, has 

 been shown to have " traveled no less than three and a quarter 

 times round the whole circumference of the earth." ^ 



Extracts from log of hark William H. Besse, from B ataxia 

 towards Boston. 



'■'■Aug. 26. This day commences with light airs and calms. 

 Light airs throughout the day. At 5.30 P. M., wind hauling 

 ahead, let go starboard anchor with thirty fathoms chain, clewed 

 up and furled all sail. Adam light bore W. 1-4 S. and E. by S. 

 Throughout the afternoon and night heard heavy reports, like 

 the discharge of heavy artillerj^, sounding in the direction of 

 Java Island. Yery dark and cloudy throughout the night, with 

 continual flashes of lightning. Barometer 30.15. 



"■Aug. 27. Commences with strong breezes, and thick, cloudy 

 weather. Barometer 30.12. At 9.30 A. M., pilot left ship. Hove 

 the lead every fifteen minutes. At daylight noticed a heavy bank 

 to the westward which continued to rise ; and, the sun becoming 

 obscured, it commenced to grow dark. The barometer fell sud- 

 denly to 29.50, and suddenly rose to 30.60. Called all hands, 

 furled everything securely, and let go the port anchor with all 

 the chain in the locker. By this time the squall struck us with 

 terrific force, and we let go starboard anchor with eighty fathoms 

 chain. With the squall came a heavy shower of sand and ashes, 

 and it had become by this time darker than the darkest night. 

 The barometer continued to rise and fall an inch at a, time. The 

 wind was blowing a hurricane, but the water kept very smooth. 

 A heavy rumbling, with reports like thunder, was heard con- 

 tinually ; and the sky was lit up with fork lightning running in 

 all directions, while a strong smell of sulphur pervaded the air, 



^ See his letter in Public Ledger, Jan. 23, 1884. 

 ^ Nature, vol. xxx, p. 12. 



