With GraphsSheet.ChartObjects(j).Chart
.ChartType = xlXYScatterLinesNoMarkers
NameRng = DataSheet.Cells(1, 2).Value
Set xRng = DataSheet.Range(DataGraphSheet.Cells(2, 1), DataGraphSheet.Cells(2, 1).End(xlDown))
Set yRng = DataSheet.Range(DataGraphSheet.Cells(3, 2), DataGraphSheet.Cells(3, 2).End(xlDown))
.SeriesCollection.NewSeries
.SeriesCollection(1).XValues = xRng ' c'est la que c'est super long
.SeriesCollection(1).Values = yRng ' et la aussi
.SeriesCollection(1).Name = NameRng
End With