[R] R information

[Catherine Eng]

Hello everybody,

I'm a beginner to R language. That's why I have some questions deal with
graphs.
In fact, I would like to know if it is possible to draw a plot with 2 y axis
against x axis (like gnuplot with the function replot)? 
In fact, I would like to plot in y1 axis, a temperature value for x values and
in the same plot, plot y2 axis which represents the density for x values. And
so  analyse the data supperposition .

I search this information into the fullmanual, but nothing help me! 
Someboby could tell me if this plot is possible? 

Thanks a lot for your attention,

Best regards,

                Catherine ENG