January 6, 1905.] 



SCIENCE. 



13 



is not easily melted or weakened by heat, 

 and above all it is inexpensive and easily 

 handled. The field is a great one, and 

 both the theory and the practise of steel 

 and concrete combinations enter, or should 

 enter, into the curriculum of every student 

 of civil engineering and architecture. In 

 the Austrian building at the recent fair in 

 St. Louis there was a model of the centering 

 of an arch, evidently steel-concrete, of 80 

 meters span (262 feet). You will remem- 

 ber that the beautiful and imposing ' Cabin 

 John Bridge,' built of granite, in Wash- 

 ington, D. C, the greatest stone arch in 

 the United States, has a span of 220 feet. 



The I'ecent enormous increase in the 

 manufacture of Portland cement is an indi- 

 cation of the coming demand. It has taken 

 thousands, perhaps millions, of years in the 

 laboratory of nature, to produce the masses 

 of granite and the layers of marble and 

 limestone ; the engineer and the chemist, 

 working together, produce from the abun- 

 dant supplies of material near at hand an 

 artificial masonry in a few hours. Of its 

 strength and durability the engineering 

 laboratory and a brief experience tell us 

 much. The verdict of a thousand years is 

 still to be rendered, but here again the hand 

 of promise points our way. 



AERIAL NAVIGATION. 



Above I casually mentioned air ships. 

 You must bear with me while I say several 

 things about aerial navigation. 



We have been accustomed to regard the 

 problem of practically navigating the air 

 as one which could not be solved, or, at 

 any rate, as a sort of fad hardly deserving 

 of mention in connection with engineering. 

 It will be remembered that the late eminent 

 engineer. Professor J. B. Johnson, would 

 not admit that aerial navigation was a pos- 

 sibility. He classed it with the problem of 

 perpetual motion. But a careful examina- 

 tion of all the conditions seems to me to 



point towards the possibility of progress, 

 and all that we can at present claim for 

 many desirable improvements is that they 

 admit of progress. We can not with any 

 confidence predict the rate of progress. 

 Some of the things I have already pointed 

 out bear directly upon the problem of aerial 

 navigation ; two in particular : The use of 

 tubular constructions for the maximum of 

 strength and the minimum of weight; and 

 the construction of motors which are strong 

 and light; but many problems must be 

 solved before we can really navigate the air. 



It was my privilege to be connected with 

 the discussion of aerial matters at the late 

 fair in St. Louis. Without my knowledge 

 I was selected as the president of the aero- 

 nautic congress, in which the problems of 

 aeronautics Avere carefully discussed. That 

 congress had no functions whatever in re- 

 gard to aerial exhibits, or attempts to ex- 

 hibit air ships, at the world's fair. The 

 latter feature of the fair I regret to say 

 was a deplorable failure. The greater part 

 of the failure was inevitable, since aerial 

 experimentation is expensive and difficult, 

 and it has very rarely been undertaken by 

 scientific people. What has been any- 

 where in that direction has been for the 

 most part crude, ill-advised and unscien- 

 tific, and faih;res have generally attended 

 any attempts to actually navigate the air. 

 Of course there are exceptions in the char- 

 acter of the investigations made. I could 

 mention four Americans who are approach- 

 ing the problem carefully and on scientific 

 lines. Some of their investigations and 

 experiments are full of promise for the 

 future of aerial navigation. 



So far as the failure of the spectacular 

 part of aeronautics at the fair was con- 

 cerned, that failure was due very largely 

 to the vandalism of some crazy crank or 

 rival, who cruelly mutilated the air ship 

 brought over by Santos Dumont at great 

 expense, to be used during the summer in 



