“RENDING FLAP.”—The rending flap is 4½ yards high, and has a surface of 4⁷⁄₁₀ square yards. It is formed of threefold Pongee silk, and is rectangular in shape, terminating in a curvilinear triangle, the point of which is turned upwards. Its vertical axis is at an angular distance of 105 degrees from each of the two manipulating valves; the lower base, which is 35⅖ inches wide, reaches down to 19⅗ inches above the equator. The seams joining the material of the “rending flap” to that of the balloon are similar to the seams of the various widths, and are likewise covered with cemented strips. In the interior of the balloon the upper extremity of the “rending flap” is of fourfold silk; its edge is put round a stick of hard wood, to which a rope for pulling is fixed, by means of which the rent is made. This rope descends to the car after having passed through the lower part of the envelope, near the appendage, in a tube. In order to make the rent with ease, which will require an effort equal to a traction of about 220 or 250 pounds, Andrée intends to use a small grapnel, which he will attach to the end of this rope and throw to the ground at the proper moment. [Illustration: THE BALLOON IN THE 96 FEET GALLERY OF THE CHAMP DE MARS EXHIBITION.] Thereupon the balloon will be emptied very rapidly, and all dragging along the ground will be avoided, however violent the wind may be. Of course Andrée will not make use of the “rending flap” until he is travelling over hospitable regions and wishes to terminate his aerial voyage and alight definitely. BANDS FOR PROTECTION AGAINST WATER.— SUNDRY DETAILS.—Above the appendage, at the parallels measuring 16 feet 4 inches and 22 feet 11 inches respectively in diameter, there are fixed, by one of their edges, two vertical circular bands nearly 4 inches high. These bands are of single silk; their purpose is to form gutters for carrying off any water which might run down the material of the balloon, and thus protect the car in which the observers are stationed from rain. In the interior of the appendage there is another band, differently placed, forming a circular trough, intended to receive any water that might result from a strong condensation of the gases contained in the balloon, and thus prevent any accumulation of such water over the automatic valve. Between the external band, of 16 feet 4 inches in diameter, and the appendage, and facing the tube through which the rending cord passes, the inflating nozzle, which is 19 feet 8 inches long, is fixed. The two cords which control each of the manipulating valves are worked by pulling: one, being that which opens the valve, is painted blue; the other, which closes it, retains the natural colour of the hemp. The cord acting upon the rending flap is coloured red.