174 Meteorology of Melbourne. 
of the climate or otherwise, of course depends on the will of 
private proprietors, and all that can be done in this particular, 
appears to consist in the erection of model dwellings, to show 
in what manner increased comfort may be obtained, without 
great Increase of cost. But in the laying out of townships, 
and the planning of streets, it appears to me that the aspect, 
with reference to prevailing winds, ought to be taken into con- 
sideration, and that if this were duly regarded, the nuisance 
of dust might ina great measure be avoided. The streets 
and apppoaches might, to a certain extent, be so laid out as to: 
direct the dust, by the shortest channels, off the town alto- 
gether. And this, in a district where the prevailing strong 
winds have so constant a character, would not, as I conceive, 
be attended with any particular difficulty. 
Before bringing this paper to a close, I must briefly advert 
to the continued droughts to which some, at least, of the 
extra-tropical portions, of the continent of Australia are 
occasionally liable. In the Sydney district a drought has 
been known to continue for eighteen months together. The 
partial failure of the crops of last season in South Australia, 
appears to be attributable principally to the unusual deficiency 
of rain during the winter months of May, June, and July. Van 
Diemen’s Land, notwithstanding its insular position, is not 
exempt from droughts. I am aware that I am now approach- 
ing the mysteries of meteorology: and it is not my intention 
to offer any bold hypothesis upon a subject which, in the 
present state of our knowledge, is undoubtedly inexplicable. 
It has by some writers been suggested, that these droughts 
are periodical, by which I understand that they should be 
liable to recur at stated intervals. Iam not aware of any 
sufficient foundation either in theory, or in fact and observa- 
tion, for such an opinion. ‘There is no particular conjunction 
of the sun, moon, or planets, which could, upon any known 
principle, give rise to a drought. I know of no reason why 
we may not have a drought next year or the year after, 
without reference to the date of the last occurrence of such 
a calamity. 
The droughts of Australia appear to be no more pe- 
riodical than the tempests which, from time to time, and, for- 
tunately at distant intervals, sweep the English and other 
coasts; and we ought at once to disabuse ourselves of this 
impression. 
According to the principles proposed in a former part of 
this paper, the fall of rain will mainly depend upon the 
frequency and the extent of the alternations of the hot 
