METEOEOLOaiCAL PERIODICITT. 159 



and ten appeared to be exceptions — that is, o£ the determined 

 years only one in six was as an exception. 



Since then I have been able, by a diligent search for informa- 

 tion, to add largely to our knowledge of the meteorology of past 

 years ; and, whatever may become in after years of the nineteen-year s 

 period, it has more in its favour now than ever before. Expe- 

 rience, however, can alone decide this question, and I have never 

 put the theory forward as the solution of our difficulty. The 

 evidence has convinced me that it represents our climatic changes, 

 but nothing will please me better than a succession of fine 

 seasons from now onwards, in direct opposition to what the pre- 

 sent investigation leads me to expect ; for such seasons would be 

 of infinitely more value than the confirmation of the theory 

 could possibly be. And I think I shall be able to show you that 

 there is an amount of probability in its favour that will justify 

 at least a careful examination ; for if it should prove true, there is 

 warning of seasons to come which may, if rightly used, be of the 

 greatest value to the grazier and the agriculturist. A page of 

 figures is not generally enticing to the reader, and I have, there- 

 fore, put into the form of curves the rainfall at each place from 

 year to year, and for convenience they have been arranged, as 

 Sydney curve is, in the nineteen-years period. It is, however, 

 impossible to convey in this way an exact idea of the character 

 of each year, for the curve is in some cases wholly distorted by 

 rainstorms, as for instance, in 1844, where the curve is raised 

 twenty inches by the rain-storm of one day ; and again in 1868, 

 a very dry year and counterpart of 1849, we have a rain-storm 

 in February in which ten inches fell. So again of 1870, it was 

 the excessive rain in March that masked the drought of six 

 months of the year ; but a very good general idea is obtained, 

 and it seems, in my opinion, to illustrate the theory that we have 

 every nineteen years a recurrence of similar weather. We have 

 already seen that much may be said in favour of a nine or ten 

 years period, that is about half the period indicated, and there 

 is doubtless this sub-period which for three or four turns seems to 

 fall in with the facts ; but if we attempt to carry it through all 

 the years it wholly fails. While tracing the nineteen years 

 period through past history, we find no less than eleven well- 

 marked lines in the series, and in many of them special charac- 

 teristics will be found reproduced step after step in the series. 



The second set of curves represents the rainfall at other places 

 in Australia, and one station (Greenwich) from the northern 

 hemisphere, which is put in for comparison ; and although the 

 theory does not at first sight seem borne out by the Greenwich 

 curve, yet there are remarkable coincidences in the character of 

 the curveSj-if they are viewed in the light of remarks to be made 

 presently. 



