[R] split a y-axis to show data on different scales

[Johannes Hüsing]

> 	  The pro's and con's of using "scale breaks" were discussed by
> Cleveland (1985) The Elements of Graphing Data (Wadsworth, pp. 85-91,
> 149).  I don't know what Cleveland said about this is the second edition

Spencer Graves:
> but I believe there are times when scale breaks are
> appropriate, but the display should make this nonstandard transition
> very clear;

... in which case you are close to having two graphs
sharing an x-axis and therefore saving on ink (yay!).