PICTORIAL RAIN MAPS. 363 
world. For example we have the rain maps published by the 
Meteorological Department of India, in which nine shades of the 
same colour (blue) are used to indicate districts in which different 
quantities of rain fall, the amount varying from 0 to 100 inches. 
The same method with variations has been adopted in America, 
Canada, Victoria, South Australia, France, Germany and other 
countries, and the same method was used by Professor Elias 
Loomis in picturing on a map of the world the amount of rainfall 
in every place where it is known. 
This method undoubtedly is invaluable to the student who is 
looaing at the question of general distribution of rain over large 
areas, but it does not give the practical and easily read details 
wanted by the agriculturalist and others. The jump from one 
shade to another is sometimes as much as ten inches, and it must 
be admitted that this method of picturing the rainfall fails to give 
that fullness of information which other methods afford, and I 
think I shall be able to show you to-night a rain map, which, 
gives the rainfall to within a quarter of an inch for each part of 
the country ; it at the same time shows the areas of equal rainfall. 
Second, we have the diagram form of rain map. One of the 
earliest of these was our own spot map as it is familiarly called, 
in which a round spot indicates the locality of each observer, and 
the quantity of rain recorded. This avoids shading in, on the 
assumption that rain has extended over districts where no measures 
have been taken. A similar method is followed in Queensland and 
Tasmania, and for some years was in use in South Australia. In 
Java a spot is used, but all are the same size, and the quantity of 
rain is shown by the number of rings in a spot not by the diameter 
of the spot, and it does not convey to the eye the relative quantity 
of rain so well as that in which the size of the spots is in propor- 
tion to the amount of rain, 
In 1880 Mr. G. J. Symons the well known author of “ British 
Rainfall,” adopted a diagram form in which a simple spot indicates 
an average quantity of rain. The signs + and — show excess or 
