72 H. C. RUSSELL. 
There are parts of the world in which you never hear of drought, 
but they tell you they have years of floods, and years of moderate 
rains, but nothing that .can be called a drought, and yet we have 
in these variations of the rainfall exactly the same causes at work, 
which make in another place a serious drought; that is, a varia- 
tion in the annual rainfall, and in the temperature and winds; 
but one place has a superabundance of rain and does not miss a 
small quantity, while the other has barely enough at any time, 
and a slight variation makes a drought. The interior of Australia 
and many other places are of this character, and our coast districts 
have a fairly abundant rainfall which modifies the drought con- 
ditions, and relatively we have little drought. In other words a 
drought is nothing if it has not a suitable local setting. 
Drought is however not wholly made by a shortage of rainfall. 
Its most important factors are great heat and drying winds. As 
an illustration we may look to the year 1895; in the latter part 
of winter and in spring, there were many falls of rain, which 
would have made grass in ordinary seasons, but it had no sooner 
fallen than a dry north-west wind and burning sun dried it all up. 
This great and burning heat was a well known feature in historical 
droughts, and some authorities say that the fable of Phaeton driv- 
ing the Chariot of the Sun so close to the earth that he set it on 
fire, is a poetical setting of an actual experience in Greece when 
the sun became so powerful that the heat was almost beyond 
endurance. . 
THE DIAGRAM. 
Before 1895 all the diagrams I used had been made to show 
quantities of the various elements, as well as their relation in time 
with a view to seeing if there was any periodicity. Recently it 
' occurred to me that it would be useful to have a diagram in which 
all the droughts without regard to their intensity should be placed 
in their order of time; not only was this desirable for seeing what 
the relation in time was, but it had become evident that it would 
be impossible to see the relation between our droughts and those 
in other countries, unléss some such pictorial arrangement WS 
