llf> Mr. H. Hilton on van der Waah r Equation. 



.'. It has a tangent parallel to the axis of x when x = $ or 1. 

 and Las two inflexions where 



x = l±_^/\, i. e. 1*577 and '423 ; approx.; 



H is of degree and class 4, has two cnsps and a double point 

 all at infinity along x = 0, has one donble tangent (the axis 

 of x, which touches it at infinity, and where #=^), and is of 

 zero deficiency. Its radios of curvature at any point is 



[16j»-4-9(3ar-1) , '(g.-l) a ]* . 



