1218 PRESIDENTS ADDRESS. 



coast is examined, but the question as to the present processes left 

 undecided, although subsidence during a comparatively recent 

 period is demonstrated. Curious irregularities of the mean sea 

 levels in Port Jackson, 1873-84 are pointed out, maxima and 

 minima differing by 1*75 inch ; but these variations are accounted 

 for by other causes than alterations in the level of the land. 



The Rainstorm which in January 1885, traversed the colony 

 from Milparinka to Jervis Bay, is compared with similar storms 

 in 1881-3, and with the Dust Storms of Feb. 6, 1885, and Dec. 12, 

 1883. 



A self-recording gauge has been erected on Lake George for the 

 purpose of registering changes of level due to evaporation, &c. It 

 has however also revealed very unexpected movements in the 

 waters of the lake, apparently of the same nature as the ebb and 

 flow of the Lake Leman and other large expanses of landlocked 

 water. Some observations upon the gravel beds of the basin are 

 of much importance as bearing upon the Geological history of this 

 singular deposit upon our ' Great Divide.' 



The same author has also contributed a paper on Local 

 Variations and Vibrations of the Earth's Surface, in which he 

 continues the same subject, and draws special attention to the 

 connection between low barometric pressure and increase of 

 instability in the earth's crust, inclining however to the view that 

 the atmospheric movements which are due to the first, may also 

 take great part in causing the latter series of phenomena. Great 

 ocean waves, such as are called Earthquake Waves, are shown to 

 occur in May and August, originating sometimes in Earthquakes 

 of severe character, but always accompanied by great barometric 

 disturbance, and coincident with the passage of our globe through 

 a meteor stream. Along with the earlier of the two periods a 

 marked fall of temperature is observable. 



Other papers are contributed as follows : — By G. H. Knibbs, 

 L.S., on a system of accurate measurement by means of long 

 steel ribands ; by Mr. L. Hargrave, on Flying Machines, 2 

 papers; by the Bev. P. Macpherson, M.A., on some causes of 



