Huniboldi's Theory of the Volcano qfJornlb. 65 



sarily a stranger ; no other description of the volcanoes of 

 Mexico having, I believe, been made public. I think, how- 

 ever, it must be allowed that the facts, of which we have the 

 relation from M. de Humboldt himself, by no means bear out 

 the theory he has proposed to account for them, but tend, on 

 the contrary, one and all, to refer the volcanic eruptions of 

 Jorullo and its vicinity to the same class of phenomena which 

 have been uniformly observed in other localities. 



In fact, in the process of argument from effects up to causes, 

 no chain of reasoning can be stronger, no conclusion can be 

 more imperative, than when, as in this instance, we are pos- 

 sessed of a considerable number of facts, all, without one ex- 

 ception, going to support a certain origin, and that not an 

 imaginary species of phenomenon invented for the occasion, 

 but the same which is observed in its continual operation on 

 other spots to produce the same results, and the only one 

 amongst all known natural processes that is capable of pro- 

 ducing them. 



I conceive, indeed, that no more effectual service can be 

 rendered to science than the destruction of any one of those 

 glaring theories, which, apparently based upon a few specious 

 facts, and backed by the authority of some great name, are 

 received by the world in general without examination, not- 

 withstanding that they contradict the ordinary march of na- 

 ture, and consequently throw the extremest perplexity into 

 that of science. 



The brilliant theory of the precipitation from one aqueous 

 menstruum of all the crystalline rocks, now beginning to be 

 reduced to its true value, is a striking example of the facility 

 with which the most baseless hypothesis may be imposed on 

 the scientific world as articles of faith, never to be called in 

 question even in thought. Let us trust it will act as a warn- 

 ing for the future. 



VOL. IV. NO. I. JAN. 1826. 



