The authors reply to Martin

Martin is certainly correct that solubility is a more complicated process than simple equations can express. While scholars may have time to return to the literature for the characteristics of each system suggested by a table of K_sp values, lecturers at the secondary and freshman chemistry levels often do not. What they need is a table of K_sp values that will yield reasonable solubilities. That is why we based our paper on empirically matching listed solubilities with simple textbook theory, rather than trying to explain the discrepancies.

Correction: In Table 3 of our paper the reference numbering is wrong. Subtract 3 from each reference number to get the correct source for the data.