thank you for your reply. Unfortunaltely this is not what I want to do. I want to use a column as a size index. The default setting for the scaling factor is "1" (It is value in the upper right edge when size of the symbol is set to a column). For my plots this "scaling" must be about 50. Do you know any way to chance this scaling via any form of scripts?
I know of no way to change that setting by script (perhaps someone else does) but you can change the default scaling factor permanently by saving the plot as a template.
As Mike suggested, how about to use a customized template from the Bubble graph type, BUBBLE.OTP? You can set and save the default base scaling factor to the template, and set up your size index in the second Y column in your X-Y-Y worksheet. --Hideo