Final calculations (reviewed): bubble (likely HgCl2 solution): 0.1mm dia, 0.1mm long -> 0.000785 mm^3 ~> 800 pl mercury total, approx (incl bubble): 0.1mm dia, 25mm long -> 0.196 mm^3 ~> 200 nl Peter P. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist