You can use a line chart, with labels of 0 through 25 through 0. These
labels will not have any numerical significance. Or you can really plot X
values ranging from 0 to 50, but add fake axis labels that follow your
pattern.

http://peltiertech.com/Excel/Charts/ArbitraryAxis.html
http://peltiertech.com/Excel/Charts/...tml#AxisScales

- Jon
-------
Jon Peltier, Microsoft Excel MVP
Tutorials and Custom Solutions
Peltier Technical Services, Inc. - http://PeltierTech.com
_______


"dave" wrote in message
...
I am trying to fit two sets of data on the same chart to make an acid/base
titration curve.
I need the horizontal axis to could from 0 to 25 then back to 0.
That way if the increments where in units of 25 the axis would be numbered
like this:

0 --------- 25 ----------0