January G, 1905.] 



SCIENCE. 



15 



ship itself could float upon the water, and 

 that mechanism was to be employed solely 

 for the purpose of driving it forward and 

 for steering it. In aerial navigati(m the 

 case is ditl'erent. The ship is not only to 

 be driven forward, but it must be sup- 

 ported. The analogous case, therefore, is 

 not that of an ocean ship, but of a heavy 

 swimmer who must both support and drive 

 himself forwai'd. Swimming does not 

 come to boy or girl by nature, and the skill- 

 ful teacher furnishes a temporary support 

 while the learner masters the art of using 

 his hands, feet and legs correctly. Ac- 

 cordingly, he applies either a buoyant bag 

 of air between the boy's shoulders, or the 

 gentle lift of a string attached to a pole, 

 and thus supports the learner while he 

 masters the mechanical details of swim- 

 ming. This exterior lift or support is a 

 diminishing quantity as the pupil pro- 

 gresses, and when correct motions are 

 learned and become automatic, the pupil 

 SAvims and external aid is no longer neces- 

 sary. 



Similarly, as it seems to me, aerial navi- 

 gation is to be accomplished. At first the 

 craft may very properly be - supported by 

 a bag of hydrogen. Something must hold 

 the structure which is to carry motor, pro- 

 pellers, fuel, ballast, steering apparatus, 

 aero-planes, etc., above the ground, in com- 

 paratively still air, while tests can be made 

 and skill in management can be acquired. 

 Infinite patience, plenty of money and 

 first-class engineering culture and skill will 

 be required. The various elements must be 

 studied one at a time, while a friendly gas 

 bag holds the experimenter aloft. When 

 an engineer can build a durable and well- 

 portioned motor and system of propellers, 

 which shall be as strong as twenty horses 

 and only as heavy as twenty geese ; and 

 when he can drive his siipporting bag of 

 hydrogen through the air at the rate of 

 twenty or thirty miles per hour, he can re- 



duce the size of his bag and get support 

 from aeroplanes and curved surfaces, and 

 learn to manage them. The smaller the 

 gas bag, the less the resistance of the air; 

 consequently a greater velocity; conse- 

 quently a greater lift of the aero-surfaces; 

 and again a less demand upon the hydrogen 

 — and so on, to final victory. American 

 skill, ingenuity and experience will tri- 

 umph provided that experience is cumula- 

 tive. Men must learn from twenty failures 

 how to succeed the twenty-first time in one 

 thing. As I said : Patience, money and 

 time are necessary. I wish Andrew Car- 

 negie, or some other 'captain of industry' 

 who is in danger of dying rich, would es- 

 tablish and endow an 'aeronautical experi- 

 ment station and laboratory,' and then 

 place it in charge of a physicist like Pro- 

 fessor Zahm, and an accomplished mechan- 

 ical engineer like Mr. Blank. In ten years 

 such men, under such conditions, would go 

 far towards a solution of the problem of 

 aerial navigation. 



FUNDAMENTAL PRINCIPLES. 



Some one proposed to teach a nation 

 patriotism by writing i:)opular songs for its 

 schools. There was a world of wisdom in 

 the suggestion, for the foundations of char- 

 acter and the guiding principles of life 

 are generally laid at school. That is why 

 the great teacher is such a power in the 

 world. 



Is it not so in engineering? Are not a 

 few fundamental propositions of mechanics 

 what one must fall back upon when a new 

 problem is encountered ? And does not the 

 probability of one's seeing new problems 

 and of solving them depend very largely 

 upon one's absolute mastery of thos^ few 

 fundamental propositions? If you agree 

 with me and answer these questions in the 

 affirmative, then it follows, in our opinion 

 at least, that the lines of progress in engi- 

 neering will depend largely upon the com- 



