We hired a launch, driven by a one-cylinder engine, from a man named Wantz, and in it proceeded up the river, taking the owner along to run the boat. It was paid for by the day, and I was warned before I started that Wantz had his own ways of lengthening journeys. I soon discovered that this was true. Before starting I had indicated the settlement which must be reached before dark, but the engine soon began to wheeze and thump dolefully. It happened that I knew something about gasoline engines, and this one sounded to me as if it were running with the spark advanced too far, but I could not discover the adjusting mechanism, so exercised diplomacy, involving Wantz in a discussion of the intricacies of modern gasoline engines, and stating that I had an automobile with a very convenient attachment for advancing and retarding the spark. He promptly and proudly showed me the device on his engine for the same purpose. It was hidden away where I could not have found it. After he had instructed me in its operation I quietly retarded the spark, and the engine began to work in a most cheering manner. In order to punish Wantz, I insisted that we keep on until we reached our prescribed destination, in spite of the time we had lost. We had a prophet of evil on board who predicted that Wantz would certainly have the engine thoroughly stacked by the next morning, and he did. We had planned to start at daylight, but, when we climbed down to the boat in the gray dawn, found him puttering over its machinery. He said that the cylinder was "froze up." As the temperature did not seem to warrant such a result, I got him to explain to me what was wrong, and after watching him put on and take off the cylinder-head several times, discovered that he had an ingenious contrivance so arranged that by giving a single push he could put the make-and-break spark connection out of commission from the inside of the cylinder. I myself adjusted it properly, compelled him to put on the cylinder-head without touching his disarranging mechanism, and we went on our way. For some time I watched him closely, and while I continued to do so, the engine ran beautifully, but ultimately I had to go ashore to inspect a rotting Manobo settlement, and while I was gone he queered it again in such a manner that I could not find the cause of the mischief. We had speedy revenge, however, for while we were negotiating a swift rapid the engine died, with the result that the launch nearly turned turtle and narrowly escaped being wrecked. This frightened Wantz, and after a few mysterious manipulations on his part the engine began to "put, put, put" again most cheerfully, and we ascended the rapid without difficulty.