The great craft, glistening in the sunlight, sailed majestically from the south, but when it reached the Cathedral it refused to turn round and face the wind. Try how he might, Mr. Spencer could not make any progress. It was a thrilling sight to witness this battle with the elements, right over the heart of the largest city in the world. At times the air-ship seemed to be standing quite still, head to wind. Unfortunately, half a gale had sprung up, and the 24-horse-power engine was quite incapable of conquering so stiff a breeze, and making its way home again. After several gallant attempts to circle round the dome, Mr. Spencer gave up in despair, and let the monster air-ship drift with the wind over the northern suburbs of the city until a favourable landing-place near Barnet was reached, where he descended. The Spencer air-ships are of the non-rigid type. Spencer air-ship A comprises a gas vessel for hydrogen 88 feet long and 24 feet in diameter, with a capacity of 26,000 cubic feet. The framework is of polished ash wood, made in sections so that it can easily be taken to pieces and transported, and the length over all is 56 feet. Two propellers 7 feet 6 inches diameter, made of satin-wood, are employed to drive the craft, which is equipped with a Green engine of from 35 to 40 horse-power. Spencer's air-ship B is a much larger vessel, being 150 feet long and 35 feet in diameter, with a capacity for hydrogen of 100,000 cubic feet. The framework is of steel and aluminium, made in sections, with cars for ten persons, including aeronauts, mechanics, and passengers. It is driven with two petrol aerial engines of from 50 to 60 horse-power. About the time that Mr. Spencer was experimenting with his large air-ship, Dr. Barton, of Beckenham, was forming plans for an even larger craft. This he laid down in the spacious grounds of the Alexandra Park, to the north of London. An enormous shed was erected on the northern slopes of the park, but visitors to the Alexandra Palace, intent on a peep at the monster air-ship under construction, were sorely disappointed, as the utmost secrecy in the building of the craft was maintained. The huge balloon was 43 feet in diameter and 176 feet long, with a gas capacity of 235,000 cubic feet. To maintain the external form of the envelope a smaller balloon, or compensator, was placed inside the larger one. The framework was of bamboo, and the car was attached by about eighty wire-cables. The wooden deck was about 123 feet in length. Two 50-horse-power engines drove four propellers, two of which were at either end.