my $datasetTemps = Chart::Gnuplot::DataSet->new(
        title   => "Dry bulb temperature",
        axes    => "x1y1", 
        ... ...

##</code><code>##

    my $datasetFrogs = Chart::Gnuplot::DataSet->new(
        title   => "Number of Frogs per day",
        axes    => "x1y2",