I am trying to add a new series to an existing chart (the existing chart works fine). This was pretty simple in Ext JS 3, but I can't figure it out in 4. Here is what I've got:

Code:
var chart = theGraph.getComponent('intakeChart');

var newSeries = Ext.create('Ext.chart.LineSeries', {
	type: 'line',
	id: 'series1',
	axis: 'left',
	yField: 'jobcount'
	});

chart.series.add(newSeries);

chart.surface.removeAll();
chart.redraw(false);
When I call this code, I get the following error:

"Uncaught TypeError: Cannot read property 'surface' of undefined"

Any ideas on what I'm doing wrong?