INTRODUCTION. 



empirical characters as the chief in regard to the rocks, 

 while he justly considers them as the last and meanest in the 

 consideration of other mineral substances. Here, as in other 

 provinces of the mineral kingdom, there is no infallible 

 guide but Chemistry j upon which alone a rational and dura- 

 ble system can be founded. And if, as some few suppose, 

 chemical operations lead us to educts instead of products, 

 the difference remains the same, and the distinctions equally 

 clear. 



Futility of Yet some ingenious men, who have made a tour of a few 

 little tours, j^^red miles, aspire to the study of geology, and speak of 

 their observations with all the pride of ignorance, and all the 

 vaunts of enterprise 5 while one simple perusal of Saussure's 

 work would teach them that they knew nothing. In the 

 momentary duration of human life, as man writes with his 

 hand on the table and his foot in the grave, infinitely more 

 knowledge must be acquired by the study of former authors, 

 than by trifling observations, which would probably not even 

 have been made if the fugitive traveller had previously studied 

 the subject, or had even once revisited the spot, as Ferrara 

 has observed of Dolomieu. While an author in his cabinet 

 studies the whole globe, and the collective labours of two 

 thousand years, these little journeys only impress him as 

 puerile excursions j and, in conversation, he regrets to find 

 the smallest tourists the greatest boasters. Da Costa has 

 illustrated this truth by a ludicrous story : Dr. Meara, having 

 the greatest respect for his own abilities, and regarding his 

 own discoveries with much admiration, was travelling on 

 Landsdown near Bath, when he observed a kind of chalk, of 

 quite a new species if not genus, being of a white colour, 

 remarkably pure, but above all very hot in the mouth -, and 

 in consequence he wrote a dissertation to prove that this 

 chalk alone was the long investigated cause of the heat of the 

 Bath waters. This celebrated discovery has passed into the 

 last edition of the valuable mineralogy of Wallerius, who 

 even quotes Da Costa as his authority for this new chalk, 



