FOREST DESTRUCTION IN NEW SOUTH WALES. 61 



very small drainage area and was dry some time between 1848 

 and 1851, and never dried up again until the end of 1885. The 

 whole of the country on the Lagoon Mountain remains in the 

 same state now as in 1348 and previous years, or since it was 

 first occupied. Here we have, I think, in the absence of any 

 regularly kept records of rainfall, tolerably good proof that the 

 drought which ended in the beginning of 1886 was at least as 

 severe as anything experienced in the 40 years previous, and yet 

 the rivulets and springs which we may say were artificially 

 produced withstood its utmost severity. 



My reason for placing these facts before you now, is to point 

 out that the extremely remarkable results which followed forest 

 destruction on Glengarry have not been of a temporary character, 

 and have not been due to a coincident change in the seasons. 

 When I wrote last, I placed before the members of this Society 

 the results of some measurements of the permanent flow of water 

 in three water-courses, which had begun to flow immediately the 

 natural forest growth had been destroyed, and which previously 

 as far back as any knowledge of them could be obtained had been 

 dry water-courses. These measurements had been carefully made 

 by myself, without regard to the flood water or freshets after 

 rain, and gave the permanent flow of water averaging the three 

 water-courses at about one-fortieth of the rainfall, and the 

 measurements were made after a somewhat dry period. The 

 whole of the water shown by these measurements was evidently 

 additional water to that which would have been found in these 

 water-courses before the forests were destroyed, though they did 

 not show the whole of the additional water. From that time up 

 to the present all these streams have continued to flow, and 

 though they were much reduced in volume towards the end of 

 1885, they did not fail to give an ample supply of water for all 

 purposes even after the Page River had stopped running in many 

 places. In addition to this, over a large area of country which 

 I have had ring-barked since 1880, precisely similar results to 

 those first recorded have followed. It is generally held, I believe, 

 that the surest test of scientific knowledge is that we shall be 

 able to predict beforehand the results that will follow from certain 

 combinations, forces put in operation, or work done. 



Now, I think, with the mass of evidence ready to our hands, 

 which has been accumulating in many parts of the Colony during 

 the last thirty years, it is quite possible to predict with absolute 

 certainty that in any given case where the character and general 

 fall of the country is such that an extra supply of water in the 

 ground would make its presence apparent in the water-courses, 

 the effect of destroying the natural eucalyptus forests will be 

 to cause a permanent increase of water in such water-courses, and 



