Rule of thirds two thirds of water, and these together, forming about one-third of the picture, the remaining two-thirds to be for air and sky; and he applies the same rule to the crossing and breaking of lines and objects, &c. Even at this early date, there was skepticism over the universality of such a rule, at least in regards to color, for Field continues: This rule, however, does not supply a general law, but universalises a particular, the invariable observance of which would produce a uniform and monotonous practice. But, however occasionally useful, it is neither accurate nor universal, the true mean
Rule of thirds (diving) Rule of thirds (diving) In scuba diving, the rule of thirds is a rule of thumb used by divers to plan dives so they have enough breathing gas remaining in their diving cylinder at the end of the dive to be able to complete the dive safely. This rule generally only applies to diving in overhead environments, such as caves and wrecks, where a direct ascent to the surface is impossible and the divers must return the way they came. For divers following the rule, one third of the gas supply is planned for the outward journey, one third is