278 



NA TURE 



[y^ily 2 1, 1887 



(20) The contractor will have the right to employ his 

 ships in whaling or sealing, and in loading guano or other 

 cargo. 



(21) Should the masters be unable to get right or sperm 

 whales to enable them to compete for the bonus offered 

 under the 12th proviso, they will nevertheless be entitled 

 to the bonus should they return with a cargo of any 

 merchantable commodity obtained within the Antarctic 

 Circle, and having a value equivalent to that of 100 tons 

 of whale oil. 



(22) Both ships must be in Port Phillip Bay and ready 

 to start on October 15. 



(23) That in case of any difficulty arising in England 

 between the Agent-General and the contractor, it shall be 

 referred to the British Antarctic Committee for decision. 



THE CAPTIVE KITE-BALLOON. 



T T has always been an objection to the extensive use of 

 ■*■ captive balloons for scientific or military purposes, 

 that a wind of moderate strength suffices not merely to 

 depress them considerably from the vertical, but to cause 

 them to jerk, rotate, and oscillate vertically and horizon- 

 tally in such a manner as to render them either partially 

 ineffective or totally useless. 



During the recent military manoeuvres at Dover, it was 

 stated that the captive balloon under the charge of Major 

 Templer was not allowed to ascend beyond the shelter of 

 the surrounding downs, owing to the strong wind then 

 prevailing. It was thus Jiors de combat as far as the enemy 

 was concerned, and this seems to be a common experience 

 of military balloonists. 



The jerking, as a balloon after a freshening of the wind 

 suddenly reaches the end of its tether, is, I am told by an 

 experienced member of the Balloon Corps, very trying to 

 the nerves, while the rotation on its axis is a serious 

 obstacle to steady observation. 



The depression of a captive balloon in a wind of any 

 sensible strength is also more than most persons would 

 imagine, and as the velocity of the wind generally increases 

 with the height (very rapidly for the first few hundred feet), 

 while the buoyancy of the balloon, owing to several causes, 

 diminishes, this condition becomes more pronounced at 

 the higher levels. 



The depression is obviously due to the fact that a 

 captive balloon, as at present employed, can only be 

 secured at its base, and thus the normal component of the 

 wind is resolved in a downward direction, pressing the 

 balloon towards the earth. If the fastening could be made 

 two-thirds of the way up its side, this normal component 

 could be resolved in an upward direction, and utilised so 

 as to add to the elevating power of the balloon. The 

 fragile nature of the balloon fabric, however, renders it 

 impossible to do this except by interposing a kite-surface 

 between it and the wind. 



All the preceding defects are remedied and several 

 positive advantages are gained by attaching a balloon to 

 a kite in the manner indicated in the accompanying 

 diagrani. 



(i) The addition of the kite with the fastening at the 

 side instead of the base counteracts the depression pro- 

 duced by the wind, and not only raises its own weight, but 

 even in a light anticyclonic breeze elevates the whole 

 apparatus to a higher level than that which could be 

 attained by the balloon alone. 



Thus, in an experiment here on Friday, June 10, in the 

 presence of Mr. Eric S. Bruce and others, with a very 

 light wind,^ the balloon of 113 cubic feet capacity and with 

 1 200 feet of wire out attained alone a mean vertical height 

 of 693 feet, while when attached to a kite of 9 feet by 



'I have since ascertained that during the trial the mean velocity at 

 Greenwich [211 feet above the sea with a good exposure for the wind (N.E.)] 

 was 12 miles per hour. The present locality was in a valley 260 feet above 

 sea-level, surrounded by hills rising to 500 feet above the sea. 



7 feet and the same length of wire it kept steadily at 789 

 feet. The lifting power in the second case was also 

 greatly increased, as shown by the following comparison 

 of the angles of the kite and wire in the two cases ^ : — 



Angle of 



The addition of the kite raised \\ lbs. more than the 

 balloon could have done alone, with a good deal to spare. 

 It increased the height by 96 feet and diminished the sag 



by 134"- 



(2) With the tail (made of self-regulating cones) it com- 

 pletely counteracts the jerky, rotatory, and oscillatory 

 movement of the balloon, by keeping the wire taut and 

 exerting a constant pull on the balloon at its lower 

 extremity. 



(3) With the addition of the top hood, an essential 



Archibald's Captive Kite- Balloon, a', octagonal kite, with frame of four 

 pieces of bamboo ; 3', spherical balloon \ f, covering of kite (preferably 

 silk) ; /, extra or top hood ; /''/', &c., bands connecting kite and hood 

 with top of balloon ; g, ring connecting lower end of kite with the con- 

 verging net cords of balloon; h, tail of cones {i); /', earlh-line connected 

 with kite, one branch passing through a pulley to the car {k). 



feature of the combination, the kite shields the balloon 

 fabric from the destructive action of the wind. 



(4) The combination can be flown on a much larger 

 percentage of days than the balloon alone. 



(5) In a large balloon with car attached the occupant 

 can alter his altitude and azimuth by pulling the lower or 

 side attachments of the kite, and thus extend his area of 

 observation, 



(6) W^ith the kite, and except in the rare case of a dead 

 calm, a much smaller balloon is needed to raise a given 

 weight.^ 



(7) The use of wire (a suggestion which I owe to Sir 

 William Thomson) greatly increases the strength, and 

 lessens the weight, of the earth-line. 



I arrived at the idea of uniting the two apparatuses while 

 conducting my kite anemometrical observations in 1884, 

 owing to my desire to prevent my kites from coming down 

 suddenly when the wind dropped. I found the balloonists 

 equally desirous of some means for shielding their balloons 

 from damage and keeping them tip in a wind. The kite- 

 balloon satisfies both requirements, and will, I trust, be of 

 use both to scientific as well as military observation. 



E. Douglas Archibald. 



Tunbridge Wells, June 25. 



' The lifting power of the balloon with hydrogen was about 5 lbs., thei 

 weighed about 4 lbs. and the kite ■3l\ lbs. 



2 The kite portion is portable and easily detachable in the event 

 calm. 



