On certain structures formed in the drying of a fluid with particles in suspension

1.Origin and Method of Experiments . I have frequently had to mount in water, for examination with the microscope, the powder of various rocks. Certain of the slides, when accidentally dried, exhibited rather interesting forms. These I showed to Professor Bonney, who encouraged me to try for farther results, so the experiments were continued with various powdered substances—many pigments (vermilion, indigo, sepia, &c.), chalk and other more or less friable rocks. At first, ordinary microscope slides were used, but afterwards, larger pieces of glass, in each case, generally with a cover-glass placed over the mud. The results seem to be worth describing, as affording familiar, almost homely illustrations which may throw some light on the origin of certain minor structures in rocks.