He went about this new development in the most methodical way. He got an insurance map of New York City, and studied the business section from Wall to Canal Streets and from Broadway over to the East River. He knew where every elevator shaft and boiler and fire-wall was, and also how much gas each resident used and what he paid for it. This last he learned by hiring men to walk through the district at two o’clock in the afternoon and note how many gas lights were burning, then to make the rounds again at three, and again at four, and so on into the hours of the next morning. With the field carefully examined he formed the New York Edison Illuminating Company, and had his assistants take charge of factories for making lamps, dynamos, sockets, and the other parts necessary for his lights. It was very difficult to get the land he wanted for his central station, but he finally bought two old buildings on Pearl Street for $150,000. He had little room space and he wanted to get a big output of electricity. So he decided to get a high-speed engine. They were practically unknown then, and when he went to an engine builder and said that he wanted a 150 horse-power engine that would run 700 revolutions per minute he was told it was impossible. But he found a man to build one for him, and set it up in the shop at Menlo Park. The shop was built on a shale hill, and when the engine was started the whole hill shook with the high speed revolutions. After some experimenting and changing they got the power that Edison wanted, and he ordered six more engines like the first. In the meantime workmen had been busy digging ditches and laying mains through the district that Edison intended to light. The engines were set up in the central station and tried out. Then the troubles began. The engines would not run evenly, one would stop and another go dashing on at a tremendous speed. Edison tried a dozen different plans before he brought anything like order out of that engine chaos. Finally he had some engines built to run at 350 revolutions and give 175 horse-power, and these proved what was required. September 4, 1882, he turned the current on to the mains for the needed light service, and it stayed on with only one short stoppage for eight years.