I found a place where none of the plants looked big enough and tough enough to impede the Mars-car and headed for the stream, which now appeared to be about twenty feet wide and very stagnant. I picked up my mike to tell Axel what I saw. Then my wheels touched the stem of a Martian saguaro shoot. I heard a whiplike crack and the whole car was enveloped in blue flame. I pressed my foot down on the accelerator and rolled over the plant. Looking back, I saw that it had fallen across another plant, a woody, slender type that was jointed like bamboo. Both of the plants were smoking. Sparks were flying from the saguaro with all the deadliness of a high power line. "What's the matter, Bill?" Axel called back. I realized that I must have shouted with surprise at the display. "These damned plants are charged with electricity, Axel. At least, one of 'em is. It just unloosed a bolt of lightning." "The hell you say! Are you hurt?" "No, the car grounded the charge," I said, "but it gave me one big scare." "Think you can bring in a sample?" he asked. "What the devil, Axel! Do you want me to be electrocuted?" "It's just an idea I had. Remember, you'll be safe in your spacesuit. It'll ground the charge, just like the Mars-car did." "Well, I'll try." I put on my helmet and got out of the car. First I walked carefully toward the banks of the stream. I avoided the saguaro-type plants, but I noticed that when my boots struck shoots and stalks of some of the other plants, sparks flew. More than half of the plants had the characteristics of an electric eel. The stream, while stagnant, was steaming. It wasn't hot water, for the temperature must have been in the low forties, but the atmospheric pressure was so light that water was evaporating in great quantities. It was difficult to see how the stream was supplied with water, since it extended between two oases, both apparently fed by the same stream. And there didn't seem to be very much flow, although after watching the stream for a few minutes I decided it was moving in the direction of Major. Then I saw tiny springs along the bank, sending little rivulets of water into the canal. It was so simple that I should have guessed where the water came from. It all came from the polar caps, of course, but the water flowed underground. The Martians had simply cut their canals to feed on the artesian supply from the North Pole. I took the can Axel had put in the locks and filled it. Then I lugged it back to the Mars-car. After I stowed the water in the locks I walked gingerly back to the saguaro I had knocked down a few minutes before. It was somewhat charred, but the fire had gone out. Apparently the air would not support much combustion. Using my knife I gingerly cut off one of the branches. No sparks flew, but I noticed that instead of sap, there was a thick, pasty pulp inside. It was acid, because before I could wipe my knife on the ground, the substance had etched itself slightly into the surface.