112 



KNOWLEDGE & SCIENTIFIC NEWS. 



[June, 1904. 



centre of effort advance. It would, therefore, seem to be 

 necessary to shift the balance in accordance with the 

 speed. The anp;le presented by the aeroplane also causes 

 this point to vary, so that experiments with the tilting of 

 the aeroplanes are also necessary. 



It is often supposed that, in addition to what we may 

 call the " passive " or " fixed " balance, we must take into 

 account the action of the air currents on the wings. 

 These may be the result both of the eddies caused by the 

 progression of the planes through still air and of gusts of 

 wind blowing against them. 



These actions and re-actions are little understood. 

 Some authorities think that a large flying machine will 

 be blown about like a piece of paper in the breeze, while 

 others declare that a hea\ y machine progressing at a 



principal experimenters in this line have unfortunately 

 lost their lives through some small deficiency in their 

 apparatus, and if tried over land there is always the 

 danger that any small mishap may result in the machine 

 losing its balance and precipitating its operator to the 

 ground. Such machines, at all events as hitherto de- 

 signed, cannot well be tried over water for several obvious 

 reasons. 



Moreover, such apparatus would usually progress com- 

 paratively slowly. Now, to support itself in the air an 

 aeroplane must move along at a very considerable speed, 

 and the questions of balance and of steering are un- 

 doubtedly much dependent on the rate of progress. 



One of the simplest means of giving an initial speed to 

 any body is to cause it to run down an inclined track 



Aeroplane leaving the Track. 



speed far greater than that of the wind will scarcely be 

 affected by it. 



Another problem calling for practical solution is that 

 of steering. Vertical and horizontal rudders may seem 

 a simple expedient, but it is doubtful if they form the 

 most efficient means of steering. A bird has no vertical 

 rudder, and tests with large gliding machines have 

 pro\ed them to be not entirely satisfactory. 



It is therefore manifest that before we can build a 

 proper airship we must make a series of trials with some 

 apparatus progressing through the air and carrying an 

 aeronaut to direct its course. Several experimenters have 

 tried gliding machines, which have been designed either 

 to soar down the face of a hill in the teeth of a wind, or 

 to be drawn along by a string. But in addition to other 

 drawbacks, these systems have the serious objection of 

 being very dangerous to the operator. .Mrcady two of the 



and to shoot off into the air at the bottom. If means 

 are adopted to pre\ent the machine from leaving the 

 track before it gets to the bottom, and if it is then pro- 

 jected over a sheet of water, there can be but little chance 

 of a serious accident. 



I therefore decided, some months ago, to erect such a 

 track, and conduct a series of experiments. Existing 

 " water-chutes " at once suggested themselves as ready- 

 made tracks, but, after examining several, and even making 

 experiments with aeroplanes on them, I came to the con- 

 clusion that such were not suitable to the purpose. They 

 are not steep enough to get up sufficient speed, they are 

 not sufficiently turned up at the bottom to shoot the 

 apparatus off in a horizontal direction, and rails and lamp- 

 posts interfere with large wings. Besides, it would be 

 difficult to arrange any method by which the aeroplane 

 could be prevented from rising off the track before 



