158 METEOROLOGICAL PEEIODICITY. 



1813-14-15-16 will ever be remembered as years of severe 

 drougbt. Again, 1822 to 1841, 1825, 1830, 1832, 1836 were wet years 



Mr. Tytler, in Ceylon, lays great stress on tbe cycle wbicb bas 

 been observed tbere for tbirty years, and be points out tbat visita- 

 tions of tbe borrible leecbes of Ceylon and most of tbe great 

 landslips occur at tbis interval, and tbat tbe Singalese, Avitb tbeir 

 traditions going back some 2,000 years, believe in an Edorvore 

 Kala and a Weyokala of tbirty years or so. 



Of longer periods we bave not mucb to say, tbougb an attempt 

 bas been made to establisb a period of fifty-six years in England 

 (5 times Hi), and I sball bave occasion furtber on to bring for- 

 ward some facts wbicb seem to point clearly to a long period of 

 upwards of fifty years in tbis Colony. 



In England Mr. Symonds's most valuable researcbes on tbe 

 rainfall bave revealed some very interesting facts upon wbicb a 

 paper could well be written, but I will bere only mention one or 

 two. In tbe middle of last century a very severe drougbt began 

 in 1737, and between 1740 and 1750 tbe rainfall was nearly 30 

 per cent, below tbe average ; after tbat it gradually rose to 

 1775, wben five wet years, 1772 to 1776, came togetber, and sucli 

 a wet period bas not been experienced since ; after tbis tbe rain 

 curve sinks rapidly again to 1785, tben a sligbt rise to 1795, tben 

 a fall to 1805, tben a gradual rise to 1824, since wbicb time tbere 

 bave been some very wet years, but tbe average keeps tbe rain 

 curve nearly even. Tbe very dry years were 1788, 1806, 1826, 

 1734, 1737-38, 1744, 1854, and 1864. Tbese facts I bave taken 

 from Mr. Symonds's work, as tbey are valuable for comparison 

 wdtb some of our bistory and traditions derived from tbe abori- 

 gines, especially tbe great drouglit, of wbicb more presently. (^See 

 diagram at end oftliis "paper?) 



Coming now to tbe period of nineteen years, wbicb I tbink 

 was first suggested in my " Notes on tbe Climate -of New Soutb 

 Wales, 1870" ; but as tbe bistory of cycle-bunting bas not yet 

 been written, it is impossible to say tbat it bas never been 

 observed or publisbed before. It is, bowever, certain tbat it was 

 tben first detected in our rainfall observations ; and, so far as tbe 

 information was tben available, it was traced back for two 

 periods. Tbe rainfall diagram from tbis point of view was tben 

 j)ublisbed, including tbe results from 1840 to 1869. Tbe follow- 

 ing year (1871), Professor Smitb, in bis oj^ening address to tbe 

 Hoyal Society of N.S.W., took up tbe subject, and added con- 

 siderably to tbe information I bad publisbed. Tbe information 

 about many years in tbe list tben available was very meagre ; 

 yet tbe evidence again seemed in its favour, as may be judged 

 from the following numerical statement : — eigbty-seven years were 

 examined ; of tbese fifty-two fell into tbe nineteen-year period, 

 twenty-five years were not determined from want of information, 



