[SciPy-User] Differentiate raw data

[Andy]

Hi People

Is there an easy way to use scipy to numerically differentiate a raw 
data series? I'm trying to do some Thermogravimetric analysis 
(http://en.wikipedia.org/wiki/Thermogravimetric_analysis), have data in 
the form of x,y and and would appreciate some wisdom to help 
differentiate the data so I could plot(using matplotlib) x, dy/dx. There 
isn't any mathematical fit to the data.

Andy