650 



PROCEEDINGS OF SECTION H. 



Brigade Head Station, under direction of Superintendent Stein, and 

 the results may be of interest. At the time the hinged cover plugs 

 were not available. 



At first test the Bateman and Moore plug, though in good order, 

 had to be cleaned of some grit. Of course this had not to be done on 

 the second occasion. The men were stationed at the plugs, and hence 

 no time was lost in searching for same. Whilst in service no lime 

 would be lost in searching for the pillar plugs, as already pointed out, 

 a considerable amount of time might be so lost with a Bateman and 

 Moore or any " roadway " plug. 



2.— THE DESIGN OF COUNTRY WATERWORKS. 



By J. W. H. HULLETT. 



3.— PARABOLAGRAPH : AN INSTRUMENT FOR DRAWING 

 PARABOLIC CURVES. 



By S. SMEATO.V, B.A. 

 Axis AN-}- point P given. — Put pin in at A. With tin square find 

 R, A P R being a right angle. Put pin on line in slotted board at R', 

 centre of slot to R' ^ N R; press corner at N' against pin A, making 

 end of line at L come on axis. Weight straight-edges in contact with 

 board. Pass pencil through loop in square at P' and into slot. Now 

 trace curve. Turn board upside down, and re-insert pin at some distance 

 from slot ; re-adjust, and trace other half of curve. Proof — y^ ^ mx ; 

 y is a mean propl. between x and 4m. P' N' = y, A N' = x, N' R' = 

 Am. P' N' is a mean propl. in the right-angled triangle A P' R'. 



