Yan Yean Water Works, 



203 



evidence, Sec, from which we had to draw our conclusions 

 and results, will be borne in mind, in forming an estimate of 

 the mode in which we have treated this important subject. 



We have the honor to be, Mr. President and Gentlemen, 

 your very obedient hmnble servants, 



F. C. Christy, C.E. 

 F. AcHEsoN, C.E. 



Art. XVI. — On the Influence of the Physical Character of 

 a Country on the Climate ; being a Letter to the President ^ 

 by R. Brough Smyth, Esq., Mining Engineer. 



Museum of Natural History, Melbourne. 

 March 8, 1855. 



Sir, 



Considerable attention being directed, at this time, to the 

 capabilities of the rivers in the colony of Victoria, in respect 

 of water supply, I have the honour to submit, for your perusal, 

 the following observations : — 



I am aware that attempts have been made, very recently, 

 to calculate the probable annual discharge of water from a 

 river by computing the drainage area, the rainfallj the eva- 

 poration, &c., but as there are other counteragcnts, equally 

 worthy of attention, and bearing directly upon the results of 

 such calculations, I propose to offer some remarks, that may, 

 perhaps, arrest the attention of those immediately inter- 

 ested. 



My present object is more particularly to inquire how 

 far the physical character, and the geological structure of a 

 country, extend their influence over peculiarities of climate 

 and in what manner they serve to determine the hydrogra- 

 phical features. This connexion. Sir, which I shall seek to 

 establish and enlarge, is, as you are aware, not new to those 

 who have made the science of Geology their study. As I 

 design to apply it, in a practical sense, to the solution of 

 some questions which have been lately brought before the 

 Philosophical Society, I feel that I shall best accomplish this 

 purpose, by divesting it entirely of purely local interest. 

 This increases the difficulties of the subject, which I ap- 

 proach with some reluctance, aware of the many and great 

 sources of error to which all such inquiries are liable ; and 



