824 



SCIENCE. 



[N. S. Vol. XV. No. 386. 



DISCUSSION AND CORRESPONDENCE. 



CAUSES OP THE SUDDEN DESTRUCTION OF LIFE IN 

 THE MARTINIQUE VOLCANIC ERUPTION. 



To THE Editor of Science: During many 

 years of teaching geology I have held in op- 

 position to most text-books on the subject that 

 explosive gases are evolved during violent 

 volcanic eruptions and that the flames seen by 

 eye witnesses do actually exist, independent of 

 lightning and the glov? of the hot lava reflected 

 from the jet of steam, etc., which are usually 

 given as the explanation of the appearance of 

 flames. 



My view has been that the heat is sufficient 

 to cause the dissociation of hydrogen and 

 oxygen from the water, on coming suddenly 

 into contact with highly heated lava; and in 

 case of sea-water the chlorine would also be 

 dissociated from the sodium. 



These gases suddenly ejected with great vio- 

 lence and exploding in the air, above the 

 crater, would produce precisely the effects wit- 

 nessed on an unusually large scale at Martini- 

 que. 



The people were mostly killed by the sud- 

 den explosion of a vast volume of hydrogen 

 and oxygen, which will account for the sud- 

 den burning of flesh and clothes, as well as of 

 the buildings and vessels. 



The chlorine, at the same time, combining 

 with some of the hydrogen would produce 

 hydrochloric acid, a poisonous and suffocating 

 gas, which would quickly kill most of those 

 not instantly destroyed by the explosion. 



A. E. Verrill. 



Yale University, 

 New Haven, Conn., 

 May 14, 1902. 



THE WHALE-SHARK (Rhinodon typicus) as an 



AMERICAN FISH. 



To THE Editor of Science : The notice by 

 J Mr. Barton A. Bean of "a rare 'whale-shark'" 

 (Science, February 28, p. 353) is the first 

 record of the Rhinodon typicus as a western 

 Atlantic fish, but the species or an allied one 

 has been several times noticed as a visitor to 

 the Pacific coast of America. Mr. Bean has 

 duly referred to my description of Micristodus 

 punctaius in 1865. When I published that 



article .1 had serious misgivings lest the species 

 would prove eventually to be congeneric with 

 Rhinodon typicus, but the positive ascription 

 to that form of simply conic teeth by such 

 eminent authorities as Miiller, Henle and 

 others restrained me from identifying the 

 California shark with it, and consequently I 

 described the American form as the repre- 

 sentative of a new genus and species. A com- 

 parison of the teeth of the California species 

 with those of the Caribbean animal has led 

 me now to consider them to be at least con- 

 generic. The later notices of the dentition of 

 individuals undoubtedly belonging to Rhino- 

 don force on me also the conviction that all 

 the selachians of like appearance are con- 

 generic. 



Mr. Bean, whom I had told that there was 

 a considerable literature on Rhinodon, in- 

 forms me that he has gone through the 

 zoological and other records without finding 

 any references other than the early one to 

 Rhinodon. This absence of data is a strik- 

 ing illustration of how unsafe it is to conclude 

 that because no references are found in the 

 zoological records, no literature exists, and I 

 now enumerate such articles as I happen to 

 know about in which Rhinodon is mentioned. 



Neglecting the general works in which 

 Rhinodon (or Rhineodon) typicus has been 

 described, we pass at once to the comparatively 

 late notices. 



In 1870 Professor E. Perceval Wright 

 noticed its occurrence about the Seychelles 

 Islands in a letter published in the ' Spicelegia 

 Biologica' printed in Dublin. This I have 

 not been able to consult as it is not in the 

 libraries of Washington or Philadelphia. 



According to Dr. Christian Liitken, however, 

 Wright (p. 65) claimed that 'this shark, which 

 is — the north whale excepted — the largest of 

 living animals, * * * contrary to the general 

 habits of the true sharks, is not a carnivorous 

 but a herbivorous fish.' 



' In 1873, Dr. Liitken compared it with the 

 basking shark, called by him Selachus maxi- 

 mus, in an article on the latter species in the 

 'Oversigt over det K. Danske Videnskabemes 

 Selskab Forhandlinger * * * i Aaret' 1873 

 (pp. 47-66, pi. 2; resume, pp. 8-10). A brief 



