122 Notes on the Rainfall Map recently 



every year. Already a very fair idea of the rainfall of 

 various districts can be formed, and most valuable informa- 

 tion on the subject obtained. To place this before the 

 public in a clear and comprehensible manner has been one 

 of the chief aims of the several colonial astronomers and 

 meteorologists upon whom the collection of rainfall statistics 

 devolves. Mr. Russell, of Sydney, has for two or three 

 years past compiled a map showing the rainfall at each rain- 

 gauge station in the year by means of a black circle, the 

 diameter of which indicates the amount. Mr. Todd, of 

 Adelaide, adopts a somewhat similar plan ; but until now I 

 have not taken any steps in this direction, principally on 

 account of the cost of carrying out a really satisfactory 

 method of doing so. Last year, however, a request was 

 made in Parliament that a rainfall map of Victoria should 

 be prepared, and the Government concurring, and under- 

 taking to provide the necessary cost, I at once set to work. 

 Some meteorological maps lately issued by the French 

 Government, and a valuable little work published in 

 America, entitled, Distribution of Rainfall Over the 

 Globe, suggested to me an admirable method of graphically 

 representing the amount and distribution of rain over the 

 colony, as far as statistics were available, by grades of one 

 colour. These methods, however, were expensive, involving 

 a separate printing for each colour, but it was suggested by 

 Mr. William Slight, the engraver of the Survey Department, 

 that by a careful system of etching and toning a similar and 

 equally good and distinct effect might be produced in one print- 

 ing. Just at this time our fellow-member, Mr. W. Culcheth, 

 who, since his residence in Australia, has taken a very prac- 

 tical interest in all matters pertaining to rainfall, irrigation, 

 &c, submitted a sketch map he had prepared from statistics 

 obtained from the Observatory, showing by different rulings 

 the amount and distribution of rainfall over Victoria. This 

 map was very carefully traced out, and I at once adopted it 

 as the basis of the new rainfall map. Indeed, I may state 

 that Mr. Culcheth had displayed such care and judgment in 

 outlining the areas that it was found unnecessary to alter 

 them, except in a very few instances, and to a trifling extent ; 

 and I must here acknowledge my indebtedness to this gentle- 

 man for the substantial help his tracing afforded me. The 

 production of nine effective tones in one colour by etching 

 and tinting was a very tedious and laborious undertaking, 

 but the result is one of which the officers of the engraving 



