XXXVI. ABSTRACT OF PROCEEDINGS. 



EXHIBITS. 



1. Mr. Russell exhibited a diagram shewing for the past 

 eleven years a progressive variation in the level, nadir and azimuth 

 of the Transit instrument, Sydney Observatory. These diagrams 

 shew an annual variation as well as a variation due to heavy rains. 

 The instrument is of the very best quality, cannot produce these 

 changes within itself, and stands upon a very massive pier which 

 was built forty years ago on the solid rock. It was shewn that 

 the progressive changes would be accounted for if the sandstone 

 is dipping to south ten degrees west, and instances were given 

 shewing that any heavy fall of rain caused a sudden change in the 

 instrument, coincident with what would happen if the weight of 

 the rain bent down the sandstone to the west of the Observatory. 

 Other Observatories had noted similar changes, notably that of the 

 Cape of Good Hope, where it was found that the instrument was 

 affected by the accumulation of water in an adjacent swamp. 



2. Professor Threlfall exhibited a large number of materials 

 required in well -equipped physical laboratories which recent 

 industrial advances have made commercially available. 



The President then addressed Professor Threlfall in the 

 following words : — " For the interesting exhibits by Professor 

 Threlfall the Society is greatly indebted. As most of you are 

 aware this meeting of the Royal Society is probably the last at 

 which we shall have the pleasure of our esteemed friend's presence, 

 inasmuch as he proposes leaving for England during the current 

 month. We cannot let this opportunity pass, therefore, without 

 publicly expressing our very great regret at losing Professor 

 Threlfall as a member of our Society, and at losing his services in 

 our University and community. On behalf of our Society, I may 

 venture to say that we very keenly appreciate his scientific 

 labours amongst us. 



"Perhaps not the least conspicuous and important feature 

 among these is the creation of the splendidly equipped physical 

 laboratory at the University, and his work and influence therein. 

 These are monuments of his energy which will live on in the life 



