that the two are but different instances of one and the same process. Of the first kind, during this last opposition, the Ganges was an example.
The Ganges was in an interesting proto-plasmic condition during the whole of last summer. About to multiply by fission, it was not at first evident how this would take place. Hints of gemination were visible when I first looked at it in August. It showed then as a very broad but not dark swath of dusky color, of nearly uniform width from one extremity to the other, with sides suggestively even throughout. It is probable that they were then, as afterward, parallel, and that the slight convergence apparent at the bottom was due simply to foreshortening. The swath ran thus north-northwest all the way from the Gulf of the Dawn to the Lacus Labeatis. By moments of better seeing, its two sides showed darker than its middle; that is, it was already double in embryo, with a dusky middle-ground between the twin lines.
In October the doubling had sensibly progressed. The double visions were more frequent, and the ground between the twin lines had grown lighter. By November the doubling was unmistakable, and the mid-clarification had become nearly complete. It is to be remarked that the doubling did not involve the Fons Juventae and the canal leading to it, both of