Class of experimental procedures for solubility determination in which a solution of known composition is prepared. Two major subclasses are recognized. In the isothermal method, one liquid component is titrated with a second liquid component at constant temperature until persistent turbidity is observed (i.e., to the cloud point). In the polythermal method, a mixture of known composition is heated above its solution temperature and monitored visually during cooling until turbidity (the cloud point) is observed.