242 
To attempt to overthrow opinions erected on so broad a basis, as 
the vast portion of chemical and mineralogical knowledge which 
Mr. Kirwan possesses, cannot but, at first sight, appear to be an act 
too presumptive to promise the least success. But when even the 
most wise and intelligent loosen the reins, and lessen those restraints 
which their judgment, in general, places on their imagination, he 
who first notices any unwarrantable deviation from established 
principles may, without fearing censure for his interference, boldly 
venture to point it out. 
The disposition of the various substances, of which the earth is 
composed, yields us so little satisfactory information ; and the data 
we thus obtain are so few, and so unconnected, as to render the aid 
of conjecture indispensably necessary. Hence, on the subject of 
the formation of this globe, and of the various revolutions it has 
suffered, the wisest men have formed the most extraordinary and 
romantic conclusions. Nor can this occasion surprise, when it is 
considered, that to point out the operations of nature, by which 
the various substances which constitute the earth obtained their 
present figure and arrangement, is, in fact, an attempt to form a 
history of the most remote periods, with the scantiest stock of ma- 
terials possible. In such a performance, success cannot frequently 
be expected; it must resemble the bold sketch of a master, who, 
whilst depicting scenes which have originated in his own rich fancy, 
strives, but perhaps ineffectually, so to correct them by his judg- 
ment, as to make them accord exactly with nature. To approach 
near to the completion of such an undertaking requires a con- 
siderable portion of genius, the efforts of which must be directed 
by a mature and correct judgment: whilst very inferior abilities 
indeed may be sufficient, to enable any one to point out an instance 
or two of disagreement, between the conjectures which are offered, 
and the circumstances they are intended to explain. This I shall, 
therefore, attempt. 
