Regarded less than half a century ago as an unnecessary luxury the elevator to-day is an imperative necessity. Sky-scrapers are equipped with both express and local elevators. The express elevators do not stop until about the tenth floor is reached. They run at a speed of about ten feet per second. There are two types of elevators in general use, one lifting the car by cables from the top, and the other with a hydraulic plunger acting directly upon the bottom of the car. The former are operated either by electric motors or hydraulic cylinders and the latter by hydraulic rams, the cylinders extending the full height of the building into the ground. America is pre-eminently the land of the sky-scraper, but England and France to a degree are following along the same lines, though nothing as yet has been erected on the other side of the water to equal the towering triumphs of architectural art on this side. In no country in the world is space at such a premium as in New York City, therefore, New York _per se_ may be regarded as the true home of the tall building, although Chicago is not very much behind the Metropolis in this respect. As figures are more eloquent than words in description the following data of the two giant structures of the Western World may be interesting. The Singer Building at the corner of Broadway and Liberty Street, New York City, has a total height from the basement floor to the top of the flagstaff of 742 feet; the height from street to roof is 612 feet, 1 inch. There are 41 stories. The weight of the steel in the entire building is 9,200 tons. It has 16 elevators, 5 steam engines, 5 dynamos, 5 boilers and 28 steam pumps. The length of the steam and water piping is 5 miles. The cubical contents of the building comprise 66,950,000 cubic feet, there are 411,000 square feet of floor area or about 9-1/2 acres. The weight of the tower is 18,300 tons. Little danger from a collapse will be apprehended when it is learned that the columns are securely bolted and caissons which have been sunk to rock-bed 80 feet below the curb.