348 M. Mohs o-/* the DUcovery of Useful Minerals. 



the mountainous tract, and thus be capable of delineating the 

 map and sections whose position and direction we can now, 

 for the first time, determine, in the most proper and advanta- 

 geous manner. For it is such maps alone, and such sections 

 alone, which can be of real service, and then- superiority con- 

 sists in this, that they are founded on no theory, but on direct 

 observations and investigations, and that they will always re- 

 main available, inasmuch as they will remain acciu-ate in all 

 time to come. 



It will happen rarely that an investigation, conducted in this 

 manner, shoidd be completed without an indication being af- 

 forded, in one way or the other, of repositories of useful min- 

 erals. But should this be the case, it is a result which has its 

 use, for it teaches us, not that there are no repositories of this 

 kind in the tract, for the search does not expose its interior, 

 but that they cannot be found out by such a procedure, which 

 is the only judicious method that can be applied, and that 

 their actual discovery must be left to the occurrence of acci- 

 dental particular events, which experience teaches us has not 

 unfrequently led to discoveries of every description. 



As it would be unseasonable and precipitate to follow after 

 every trace of a repository of ore, of whatever description it 

 might be, at its first discovery, (except where the discovery 

 were of such consequence that we might be satisfied at once 

 of its value), so is it now time to follow up these traces and 

 indications with all zeal and perseverance, as this can now be 

 done with the requisite auxiliaries, and, therefore, with the 

 hope of a favourable result. I do not mean that a discovery 

 of this kind should be entirely overlooked during the prosecu- 

 tion of the search in the progress of which it has been made ; 

 but only that the course of investigation should not be inter- 

 rupted, and that an unnecessary amount of time should not be 

 bestowed on it, inasmuch as the most appropriate means of 

 making the most advantageous use of it cannot be ascertained 

 till a later period. 



If the presence of useful minerals has been indicated by the 

 sand of the banks or channels of the rivers, or by the frag- 

 ments and boulders on the declivities of the hills, we shall at 

 least be able to say where we may, with the probability of sue- 



