362 Proceedings of the Royal Society of Victoria. 



752 to 756 feet. The intervening country was comparatively 

 level and open. 



3. A barograph was left at Croydon Railway Station. Three 

 aneroids were taken to the top of Mount Dandenong, six miles 

 distant, and nearly 1700 feet higher. Each aneroid was read 

 nine times, beginning at 10.30 a.m., and ending at 4 p.m., and 

 the height of the mountain computed, taking Croydon as the 

 datum point. The three aneroids gave 2064, 2057, and 2046 

 feet respectively, above sea level, while the trigonometrical 

 survey height on the large Government map of Victoria is 2060. 



4. A barograph was left at Moe Railway Station. Thi'ee 

 aneroids were taken to a point on Mount Baw Baw, 25 miles to 

 the north, and about 5000 feet above Moe, and read once only, 

 as the party had to return immediately. The results on being 

 worked out gave 5235, 5301, and 5258 feet above sea respectively, 

 for the three instruments. On a subsequent occasion a party 

 camped for several days at the same place and made hourly 

 readings of two good mercurial barometers, the results of 

 which gave 5200. 



5. The instrument mentioned in example 2 was taken hy 

 railway from Sydney to Brisbane, 720 miles, over country rising 

 at one point 4500 feet above sea, and agreed throughout with the 

 railway levels within 3 per cent. It was also taken by railway 

 from Durban to Capetown, in South Africa, via Pretoria, a 

 distance of fully 1500 miles, the country rising in parts to over 

 5000 feet above sea, and give the heights of tlie railway stations 

 within 5 per cent, of the truth. These results should answer 

 doubts that have been expres.sed as to the utility of aneroid 

 levelling in extensive explorations. 



General Reco.mmkndations. 



Properly tested aneroids, used with judgment and suitable 

 precautions, are capable of doing very useful work, but too much 

 must not be expected from them. They should be used in 

 conjunction with a barograph placed preferably at a railway 

 station or other point, the level of which is accurately known. 

 From such a point as a centre, it is possible to do fairly good 

 work for a radius of say 20 miles in open country, and 10 miles 



