76 H. I. JENSEN. 



lasting from 1875 - 79. But at the great minimum of 1864 

 to 1869 Port Louis in Mauritius had a much lower rainfall 

 than usual, and at the great maximum 1870, the Port Louis 

 rainfall again rose to more than normal. It may be noted 

 that the sunspot minimum of 1864 — 1869 was accompanied 

 by droughts in Australia, Orissa, Bengal, Russia, and South 

 America as well, and as has already been shown by me, 1 

 this was a period of intense volcanic disturbances and 

 earthquakes, especially the years 1867 and 1868. 



It is well known that in years of great drought, as this 

 last one of 1897 — 1902, which we have just passed through, 

 heavy rains are often experienced out at sea. It seems that, 

 perhaps on account of the deficiency in our supply of solar 

 energy, our atmosphere circulates too feebly to bring the 

 moisture landwards. The vapours are not brought into the 

 higher regions at all, and consequently condense over the 

 areas whence they were drawn. Mauritius, an island, 

 lying in our warmest ocean, and not many hundred miles 

 from where the cold Antarctic drift often carries its ice- 

 bergs along, is particularly liable to receive rain when 

 other parts of the earth, less advantageously situated, have 

 to suffer. Geographical considerations like the above, 

 would perhaps, go far to explain anomalies in rainfall. 



The following quotations from a book by Prof. J. W. 

 Gregory, dsc., f.r.s., entitled " The Climate of Australasia," 

 seem pertinent to the subject just discussed : — 



(1) " We cannot expect that rainfall will anywhere vary with 

 mathematical regularity. Rainfall is one of the most complex of 

 meteorological products, and is the resultant of a series of con- 

 flicting agencies." 



And (2) discussing the rainfall of Mauritius — 



"It is found at this period the south-western monsoon gives 

 India its maximum of rainfall, while India as a whole, being con- 



1 Proc. Roy. Soc. N. S. W\, June, 1902. 



