Since rapid transit is as much a matter of commercial importance as of mere personal convenience it must not be supposed that an average of 50 miles an hour will continue to meet the needs of travellers. Already practical experiments have been made with two systems that promise us an ordinary speed of 100 miles an hour and an express speed considerably higher. One of these, the monorail or single-rail system, will be employed on a railroad projected between Manchester and Liverpool. At present passengers between these two cities--the first to be connected by a railroad of any kind--enjoy the choice of three rival services covering 34-1/2 miles in three-quarters of an hour. An eminent engineer, Mr. F. B. Behr, now wishes to add a fourth of unprecedented swiftness. Parliamentary powers have been secured for a line starting from Deansgate, Manchester, and terminating behind the pro-Cathedral in Liverpool, on which single cars will run every ten minutes at a velocity of 110 miles an hour. A monorail track presents a rather curious appearance. The ordinary parallel metals are replaced by a single rail carried on the summit of A-shaped trestles, the legs of which are firmly bolted to sleepers. A monorail car is divided lengthwise by a gap that allows it to hang half on either side of the trestles and clear them as it moves. The double flanged wheels to carry and drive the car are placed at the apex of the gap. As the “centre of gravity” is below the rail the car cannot turn over, even when travelling round a sharp curve. The first railway built on this system was constructed by M. Charles Lartigue, a French engineer, in Algeria, a district where an ordinary two-rail track is often blocked by severe sand-storms. He derived the idea of balancing trucks over an elevated rail from caravans of camels laden on each flank with large bags. The camel, or rather its legs, was transformed by the engineer’s eye into iron trestles, while its burden became a car. A line built as a result of this observation, and supplied with mules as tractive power, has for many years played an important part in the esparto-grass trade of Algeria. In 1886 Mr. Behr decided that by applying steam to M. Lartigue’s system he could make it successful as a means of transporting passengers and goods. He accordingly set up in Tothill Fields, Westminster, on the site of the new Roman Catholic Cathedral, a miniature railway which during nine months of use showed that the monorail would be practical for heavy traffic, safe, and more cheaply maintained than the ordinary double-metal railway. The train travelled easily round very sharp curves and climbed unusually steep gradients without slipping.