Professor Lowell is of opinion that these carets must fulfil some important purpose, as they only appear where some of the canals connect with the dark areas of the old sea-beds. He is quite right in this conclusion, for they are very important indeed in connection with the working of the canal system. They are, in fact, all situated on or adjoining the slopes of the sea-beds, and the dark sides of the V are really two high embankments covered with dense vegetation, and thus are sufficiently conspicuous to be seen through our telescopes. The whole encloses an area on each side of the canals within which large and important engineering works are situated. The canals which run along the bottom of the sea-beds are, of course, at a much lower level than the adjoining red area, and the canals on the latter area are therefore at a higher level. Those canals which cross the sea-beds cannot be carried by means of viaducts or embankments so as to place them upon the same level as the canals on the red areas, because that would defeat the purpose of irrigation, which is their chief use. It is therefore necessary to lift the water from the low-level canals and discharge it into those upon the higher ground. This is accomplished by means of apparatus somewhat resembling an American "grain-elevator," on a large scale; and it consists of a long series of very large buckets, V-shaped in cross-section, attached to endless chain-bands, which, as they are carried round by the machinery, scoop up the water from the low-level canals and carry it up to the requisite height, from whence it is automatically discharged into the high-level canals. Of course it will be understood that the ends of the latter canals are entirely closed by embankments so that no water can pass that way. The buckets are an enormous size, and the electric machinery by which they are kept in motion is of the most ingenious description. Besides this there is an immense amount of equally ingenious electrical machinery for forcing the water along the canals. Merna and Tellurio showed us all over the area, and carefully explained the construction and working of the various machines. I do not think M'Allister ever spent a more enjoyable time in his life, for he went about amongst the different machines examining them with the keenest interest and manifestations of delight; and his note-book was in constant requisition for making sketches and notes of what he saw. We noticed that he was frequently smiling and chuckling to himself as if he were intensely pleased; and presently he came over to us, rubbing his hands together in high glee, and said to John, "Heh, mon, I reckon I see my way to making a fortune when we return home, out of the ideas and wrinkles I'm getting here from the work of the Martian engineers!" John laughed, and congratulated him heartily on his brilliant outlook for the future, remarking that he did not appear to regret coming to Mars.