<div class="htmlview paragraph">The mechanism of spray formation at high velocities is so complicated that it cannot be subjected to a complete mathematical treatment. Despite numerous studies made since Plateau, no reliable formula known can calculate directly and accurately the spray characteristics such as cone angle, spray velocity, droplet size, and droplet distribution indiesel engines. Here, an attempt is made to eliminate the complex, laborious, high pressure part of spray measurement and to calculate spray penetration by carrying out spray measurements in the atmospheric air alone.</div>