The canals so far described all lie in the bright reddish-ochre portions of the disk,--those parts which bear every appearance of being desert. But Mr. Douglass has made the discovery that they are not the only part of the planet thus privileged. He finds, in the very midst of the dark regions themselves, straight, dark streaks not unlike in look to the canals, and still more resembling them in the systematic manner in which they run. For they reproduce the same rectilinear arrangement that is so striking a characteristic of their bright-area fellows. He has succeeded, indeed, in thus triangulating all the more important dark areas.

Now this is a very interesting discovery, from several points of view. In the first place, it proves another tell-tale circumstance as to the true character of the so-called seas; for that the seas should be traversed by permanent dark lines is incompatible with a fluid constitution. But the lines are even more suggestive from a positive than they are from a negative standpoint. For they make continuations of the lines in the bright regions, showing that the two are causally connected, and affording strong presumption that this causal relation is the very one demanded by the theory of irrigation. For if the canals in the bright regions be strips of vegetation irrigated by a canal (too narrow to be itself visible at our distance), and there be a scarcity of water upon the surface of the planet, the necessary water would have to be conducted to the mouths of the canals across the more permanent areas of vegetation, thus causing bands of denser verdure athwart them, which we should see as dark lines upon the less dark background. Indeed, it is exactly what we should expect to find if the theory here advanced be true. For it is the very next logical step in that theory made visible. If the canals in the bright regions are to be fed from the melting of the polar cap, it is altogether likely that they would be connected with it by other canals running through the dark regions. We might, therefore, expect to see lines in the dark regions not unlike the lines in the bright ones, and if these lines were of the same character as those in the bright regions they would betray this character by connecting directly with them. Now this is precisely what he finds the two sets of lines do. His canals in the dark regions end at the very points at which the others begin; and they do this invariably. There is no canal in the dark areas which does not so connect with one in the bright regions.

Finally, some of the most southern appear to run tolerably straight toward the pole; but of the plan underlying the whole system of Martian canals we cannot at present predicate details; as, though the system instantly suggests plan, it suggests a plan that does not instantly commend itself to human comprehension.

Mr. Douglass finds 44 of these canals, not including the straits between the islands, as is shown in the following list: --

 Name No of drawings in 
 ---------- which it appears. 
 Acalandrus 19 
 Acesines 19 
 Acis
14 
 Aeolus 13 
 Amphrysus 1 
 Athesis 16 
 Caicus 8 
 Carpis 3 
 Casuentus 21 
 Cayster 3 
 Cestrus 2 
 Chaboras
4 
 Cinyphus 14 
 Cyaneus 6 
 Cyrus 3 
 Dargamanes 20 
 Digentia 2 
 Dosaron 10 
 Drahonus 5 
 Erannoboas
17 
 Erymanthus 21 
 Eurypus 9 
 Gaesus 2 
 Galaesus 6 
 Garrhuenus 12 
 Harpasus 2 
 Helisson 12 
 Heratemis
4 
 Hipparis 19 
 Hippus 13 
 Hyctanis 4 
 Hydriacus 1 
 Hylias 7 
 Hyllus 14 
 Leontes 2 
 Malva 8 
 Mogrus 2 
Nestus 5 
 Neudrus 10 
 Oceanus 37 
 Opharus 13 
 Orosines 29 
 Padargus 5 
 Tedanius 25

It is interesting thus to forestall objection about a missing link by discovering that link thus early.

Before passing on to certain other phenomena connected with the canals of like significance, we may note here an obiter dictum of the irrigation theory of some slight corroborative worth; for, if a theory be correct, it will not only fit all the facts, but at times go out of its way to answer questions. Such the present one seems to do. If the seas be seas, and the canals canals, we stand confronted by the problem how to make fresh-water canals flow out of salt-water seas. General considerations warrant us in believing that the Martian seas, like our own, would contain salts in solution, while irrigation ditches, there as here, should flow fresh water to be most effective, and we seem committed to the erection of distilleries