Page:Popular Science Monthly Volume 61.djvu/392

386 the old too has often remained either unknown or ignored, buried in the books which nobody reads. Thus the whole chain of argument is rarely available to those not engaged in the investigation, and the conclusions reached appear to hang on slenderer threads than is really the case. It has seemed to me, therefore, not without profit to collect into one the various views of the cartography of Mars, so much, that is, as is essentially original and not mainly confirmative of the work of previous observers. To this intent, I have produced the new maps, reproduced the old and set them opposite one another. Thus brought face to face they make a rather impressive self-confessed avowal of relationship.

Twelve maps constitute the series. Each marks the point areography had reached at the time. No map has been left out which added anything new except when a contemporary added more. The twelve maps arranged in chronological order are these:

As is commonly the case when things are summed up, much more results than one anticipates. It always turns out that one has spent more than he imagines; and fortunately with accumulations it is sometimes the same. Much emerges thus from the present assemblage and three points in particular stand out to command attention. The three points will be found to be:

1. The fundamental agreement of the whole series.

2. Evidence that the peculiarity of the markings seen by Schiaparelli was not the fathering of fancy, but a recognition forced upon him by the markings themselves.

3. A visible evolution in discovery which has steadily progressed from the beginning to the present day marked by three stages—pre-Schiaparellian, Schiaparellian and what we have learned since.

To be struck by these three deductions it is only necessary to compare the several maps with one another when one shall have learnt so much of the circumstances of each as to make their relations understandable.