Size Property
Returns or sets the font or marker size (in points). Returns Null if it is used on a range in which the characters are not all the same size. Use the IsNull function to determine whether the return value is Null. Read/write Variant for the Font object; read/write Long for all other objects in the Applies To list.
expression.Size
expression Required. An expression that returns one of the objects in the Applies To list.
Example
This example sets the font size to 6 points for the specified axis.
Set c = ChartSpace1.Constants
ChartSpace1.Charts(0).Axes(c.chAxisPositionLeft).Font.Size = 6