INORGANIC GEOLOGICAL DYNAMICS. 545 



may at least be able to show the improbability of some conjectures 

 which have been propounded. 



I shall now give a very brief account of some of the attempts made 

 in these various departments of this province of our knowledge ; and 

 in the present chapter, of Inorganic Changes. 



Sect. 2. Aqueous Causes of Change. 



THE controversies to which the various theories of geologists gave 

 rise, proceeding in various ways upon the effects of the existing causes 

 of change, led men to observe, with some attention and perseverance, 

 the actual operation of such causes. In this way, the known effect 

 of the Khine, in filling up the Lake of Geneva at its upper extremity, 

 was referred to by De Luc, Kirwan, and others, in their dispute with 

 the Huttonians ; and attempts were even made to calculate how dis- 

 tant the period was, when this alluvial deposit first began. Other 

 modern observers have attended to similar facts in the natural history 

 of rivers and seas. But the subject may be considered as having first 

 assumed its proper form, when taken up by Mr. Von Hoff ; of whose 

 History of the Natural Changes of the EartKs surface which are 

 proved by Tradition, the first part, treating of aqueous changes, ap- 

 peared in 1822. This work was occasioned by a Prize Question of 

 the Royal Society of Gottingen, promulgated in 1818 ; in which these 

 changes were proposed as the subject of inquiry, with a special refer- 

 ence to geology. Although Von Hoff does not attempt to establish 

 any general inductions upon the facts which his book contains, the 

 collection of such a body of facts gave almost a new aspect to the 

 subject, by showing that changes in the relative extent of land and 

 water were going on at every time, and almost at every place ; and 

 that mutability and fluctuation in the form of the solid parts of the 

 earth, which had been supposed by most persons to be a rare excep- 

 tion to the common course of events, was, in fact, the universal rule. 

 But it was Mr. Lyell's Principles of Geology, being an attempt to ex- 

 plain the former Changes of the Earth's Surface by the causes now 

 in action (of which the first volume was published in 1830), which 

 disclosed the full effect of such researches on geology ; and which at- 

 tempted to present such assemblages of special facts, as examples of 

 general laws. Thus this work may, as we have said, be looked upon , 

 as the beginning of Geological Dynamics, at least among us. Such 

 generalizations and applications as it contains <j;iv'j the most livelv 

 VOL. II. 85. 



