Spherical ballooning, some of the requirements
A 1917 manual on spherical balloon construction and handling by Paul James McCullough, printed in Saint Louis by the Mangan printing company for balloonists and pilots. Its pictures are simple line diagrams of a gas-balloon envelope, a red gasoline thermometer tube, rip panel and drag rope arrangements, and a balloon over dotted terrain, offering a designer clean schematic linework with a warm cream paper tone and a clear arrow motif for direction.
