VOLCANOES, THEIR ACTION AND DISTRIBUTION 43 



four vessels could find employment, and the crews of them had to do 

 additional work on shore in order to support themselves, the returns 

 from the beds being so inadequate. 



The evil of excessive fishery then exists, and, continuing, can have 

 but one effect, and we have seen how disastrous is that result. Our 

 oyster-beds are, however, so extensive, the animals are so widely dis- 

 tributed, and are so easily transported and transplanted, that the total 

 failure of the American oyster-beds must be postponed for some time. 

 But the failure of the beds of different localities may occur at any time, 

 and it is more than probable that those of Chesapeake Bay will be 

 practically exhausted before many years. The deterioration and final 

 exhaustion of the beds, either of particular localities or of the whole 

 country, would, however, cause far greater distress, discomfort, and 

 inconvenience in the United States than the failure of the foreign beds 

 caused abroad. With us the oyster is no luxury, but a means of sub- 

 sistence to a large number of people. Oysters are consumed from 

 Maine to Texas, and from the Atlantic to the Pacific, and immense 

 numbers are also annually exported. In supplying this great demand 

 numbers of the poorer classes of citizens find a constant and profitable 

 employment, and thus the deterioration of the beds, or extinction of 

 the oysters, would not only be felt by the consumer in the much-in- 

 creased price of a desirable and nutritious article of food, but by the 

 producer, in a loss of employment, and that loss occurring in localities 

 where there is hardly any other resource. 



[The natural history of the oyster with especial reference to the 

 process of reproduction and the conditions influencing its rate of in- 

 crease will form the subject of a concluding article. Ed.] 



VOLCANOES, THEIR ACTION" AND DISTRIBUTION * 



" TT7TIAT is a volcano ? " This is a familiar question, often ad- 

 V V dressed to us in our youth, which " Catechisms of Universal 

 Knowledge " and similar school manuals have taught us to reply to in 

 some such terms as the following : " A volcano is a burning mountain, 

 from the summit of which issue smoke and flames." This description, 

 says Professor Judd, is not merely incomplete and inadequate as a 

 whole, but each individual proposition of which it is made up is grossly 

 inadequate and, what is worse, perversely misleading. In the first 

 place, the action which takes place at volcanoes is not " burning," or 

 combustion, and bears, indeed, no relation whatever to that well-known 



* Volcanoes, what they Are, and what they Teach. By JohD W. Judd, F. R. S. With 

 Ninety-six Illustrations. "International Scientific Series." In press of D. Appleton 

 &Co. 



