Issued by the Government of Victoria. 123 



and lithographic branch of the Survey Office, who took 

 immense interest and pains in the work, may well be proud. 

 This method of grading, being once accomplished, is avail- 

 able for any future maps, so that for nexfc year's map the 

 work will be trivial as compared with this first one. The 

 map consists of the new map of Victoria, combined with 

 the south part of New South Wales and the west part of 

 South Australia, upon which is printed in blue colour nine 

 grades or tones, each grade being confined within certain 

 irregular curved outlines or boundaries, forming a somewhat 

 arbitrary limit to the areas, over which the rainfall was 5 to 

 10, 10 to 15, 15 to 20, and so on up to 50 or more, inches per 

 annum. It must be remembered that these curved outlines 

 have been put in with a somewhat free hand, and they must 

 not be taken as strictly representing a margin beyond which 

 the rainfall is 5 in. more or less than within it. Neverthe- 

 less, as the contour of the country, some topographical know- 

 ledge, as well as rain-gauge statistics, have been taken into 

 account in tracing them, they may confidently be assumed 

 as sufficiently near for all practical purposes. There are two 

 or three prominent facts displayed by this map : — 1. That 

 the greatest rainfall takes place on the coast lines or on the 

 summits of the high ranges, especially near the coast. 2. 

 That the areas immediately in the lee of these ranges have 

 a markedly lessened rainfall. 3. That, were it not for the 

 mountain ranges, it appears probable the amount of rainfall 

 in the southern and eastern portions of Australia would 

 decrease gradually from the coast line to the central regions 

 of the continent. It is proposed to issue a similar map every 

 year ; and I hope the one for the current year will be ready 

 by February. It would be very interesting to have a map 

 showing the average rainfall for many years, but the 

 materials available for one to show an average five years 

 are, I fear, as yet somewhat too meagre. 



Art. XIX. — The Return of the Pons Comet 

 By Mr. Ellery, F.RS. 



[Oral communication 15th November, 1883.] 



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