1034 



SCIENCE. 



[N. S. Vol. XV. No. 391. 



formed and it concentrates around the dust 

 particles and falls in a rain of mud. The re- 

 ports show that the mud fell, not near the 

 crater, but along the lower part of the moun- 

 tain. 



As soon as the outrushing hydrogen could 

 combine with the oxygen of the air to form 

 water, an immediate contraction followed. 

 A vacuum was formed extending over areas 

 in proportion to the volume of hydrogen 

 ejected, and combined with the atmosphere. 

 Hurricane phenomena on a gigantic scale 

 were at once witnessed. Trees were uprooted 

 and the walls of houses were pulled outwards. 

 The clothes of the victims were torn off. 

 The garments had acted like the screens on 

 the Davy safety lamp — they had prevented the 

 air between body and clothes from combining 

 with the hydrogen, but as soon as the vacuum 

 caused by the combination on their exterior 

 took place they were exploded and torn off by 

 the contained air. The extensive vacuum thus 

 formed might also account for the sudden 

 death of the victims, the instantaneous re- 

 moval of the atmospheric pressure causing 

 cerebral hemorrhage and paralysis. Autopsies 

 upon the bodies of the victims would have de- 

 termined the immediate cause of death. If 

 none have been made they might still be 

 made where the bodies were well covered. 



In the absence of other demonstrable causes 

 the tidal wave may also be accounted for on 

 the same theory. Eob't H. Gordon. 



Cumberland, Makyland, 

 June 7, 1902. 



SHORTER ARTICLES. 



BLACK RAIN IN NORTH CAROLINA. 



The 'famous black rain,' so-called by the 

 natives, fell at Louisburg, N. C, the morning 

 of March 15, 1900. 



A sample of the water which had been care- 

 fully collected came into our hands through 

 the kindness of Professor M. S. Davis, of the 

 Louisburg Female College. An analysis was 

 made: 



Parts per Million. 



Total residue 88.00 



Loss on ignition 54.00 



Non- volatile residue 34.00 



Parts per Million. 



Chlorine 19.144 



Oxygen consuming power — 15 minutes. . 1.93 

 Oxygen consuming power — i hours .... 2.64 



Ammonia — free 872 



Ammonia — albumenoid 04 



Nitrogen as nitrates 88 



Nitrogen as nitrites none. 



About sixty per cent, of the residue was 

 organic matter, largely soot. The chlorine 

 content showed an unusual amount of sodium 

 chloride. The non-volatile residue besides so- 

 dium and some calcium gave reactions for 

 traces of iron, manganese, aluminum and 

 zinc. The other constituents indicate ordinary 

 rain water. 



No especial phenomena were noted preced- 

 ing or during the precipitation 'except an un- 

 usually black cloud and a heavy downpour of 

 rain, accompanied by a darkness so dense as 

 to necessitate the use of lamps for half an 

 hour.' It had been raining for several days 

 preceding this occurrence and the water col- 

 lecting in pools out of doors showed a distinct 

 and unusual black color. A number of sam- 

 ples were collected and held as a curiosity. 

 After a few days the water became clear 

 through the settling of a black sediment. 



The situation of and amount of fuel burned 

 in the place, as well as the time of the year, 

 preclude accounting for the fluorescent black 

 rain by local contamination, such as ob- 

 served in numerous cases by Angus Smith 

 and Phipson and lately by Irwin, who exam- 

 ined the snowfall in Manchester, England 

 (Journ. Soc. Ohem. Ind., XXI., 533, 1902). 

 "\\niile it is well known the unusual impurities 

 in rain, snow, etc., often occur and the sources 

 of contamination may be traced great dis- 

 tances, no opinion is hazarded as to the cause 

 of this phenomenon. All such incidental ob- 

 servations deserve chronicling, as did the black 

 snow which fell in Indiana in January, 1895 

 (Monthly Weather Review, 60, 19), the 'blood 

 rain ' reported by Passerine to have fallen at 

 Florence in March of last year {L'Orosi, 24, 

 825), and the 'dust fall' in Europe the same 

 month (reported by Hellmann and Meinar- 



dus). ChAS. B.4SKERVILLE, 



H. R. Weller. 

 University op North Carolina. 



