Once this relationship was established by Chézy, many engineers and physicists (see the below section Authors of flow formulas) continued to search for ways to improve Chézy's equation. A slight oversight of Chézy's formula was determined by the research of these colleagues. They determined that the velocity's slope dependence in Chézy's formula (V:S 0) was reasonable, but that the velocity's dependence on the hydraulic radius (V:R h) was not reasonable and that the relationship was closer to (V:R h). Many formulas based on Chézy's formula have been developed since its discovery by these contemporaries and others, and differing formulas are more suitable in differing conditions.