ABSTRACT OF PROCEEDINGS. Xlli. 



ABSTRACT OF PROCEEDINGS, JUNE 6, 1900. 



The General Monthly Meeting of the Society was held at the 

 Society's House, No. 5 Elizabeth street North, on Wednesday 

 evening, June 6th, 1900. 



The President, Prof. Liversidge, m.a., ll.d., f.r.s., in the Chair. 



Thirty-one members and one visitor were present. 



The minutes of the preceding meeting were read and confirmed. 



One new member enrolled his name and was introduced. 



Dr. Marden and Mr. T. H. Houghton were appointed 

 Scrutineers, and Mr. C. O. Burge deputed to preside at the 

 Ballot Box. 



The certificates of two candidates were read for the third time, 

 of four for the second time, and of two for the first time. 



The following gentlemen were duly elected ordinary members 

 of the Society : — 



McKay, G. A., Chief Mining Surveyor, Department of Mines. 

 Wallach, Bernhard, b.e. Syd.; Darlinghurst. 



THE FOLLOWING PAPERS WERE READ : 



1. "On the relation, in determining the volumes of solids, whose 

 parallel transverse sections are n ic functions of their position 

 on the axis, between the position and coefficients of the section 

 and the (positive) indices of the functions," by G. H. Knibbs, 

 f.r.a.s. 

 The integral of the function 



A z = A + Bz v +Cz* + Dz Y + etc (1) 



Vlz ' Rz v Cofl- D? T 



V=fA z dz = z(A+^-+- i ^+J L ^ i -fete.) (2) 



will represent an area if A z be an ordinate, or a volume if it be an 

 xy plane. In the former case the boundaries of the area are the 

 curve, the axis, and the ordinates at z x and z 2 ; in the latter case 

 the xy planes at those abscissae am the parallel terminal planes of 

 a volume generated by the motion of one of them, its area how- 

 ever changing in terms of the function. No loss of generality 

 occurs by making z 2 - z k unity in (2), since the origin and unit 



