Proceedings of Sections. 



Section A. 

 ASTRONOMY, MATHEMATICS, AND PHYSICS. 



1.— OX THE CONSTRUCTION OF PENDULUM APPA- 

 RATUS FOR DIFFERENTIAL OBSERVATIONS OF 

 GRAVITY. 



By E. F. J. LOVE, M. A., Fellow and Rector of Queen's College, Assistant 



Lecturer and Demonstrator in Natural Fhilosophy to the 



University of Melbourne. 



[Abstract.] 

 In this paper the author lays down certain main principles, to 

 ■which attention shoiild be paid in the design of invariable pendu- 

 lums. Exception was taken to pendulums of the flexible pattern 

 designed by Kater, and reasons advanced for preferring the more 

 rigid form adopted by von Sterneck. The forms of stand previously 

 employed were also criticised and an improved pattern suggested. 

 The paper concluded with a discission of the methods adopted for 

 investigating the temperature and pressure corrections. 



2.- ON SOME DIAGRAMS SHOWING THE RELATION 

 BETWEEN THE LENGTH OF A SOLENOID AND 

 THE FORM OF ITS EQUIPOTENTIAL SURFACES. 



By C. COLERLBGE FARE, B.Sc, Mathematical Tutor in St. Paul's 

 College, University of Sydney. 



Plates II.- V. 



Some months ago the author had occasion to design a solenoid, 



in which the variation of the field strength between the axis and 



the inside edge for a short distance on either side of the equatorial 



plane should not exceed a certain amount. For this purpose it 



