Hi both,
Thank you very much for your responses. Whilst I knew one could throw in the towel, throwing in the sponge is not something I've heard of before! So, thank you for adding to my knowledge - and for the interesting information on where both phrases come from :-)
As for my handle...I am studying for a chemistry PhD: but, because my research is computational, and can thus be done from virtually anywhere, I am rarely found in the department, choosing to work elsewhere. I thus conside myself to be an elusive chemist!!