e 
146 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1909. 
attain. But it is not a question of awarding prizes to engineers. 
We want to know what air-ships have the greatest practical advan- 
tages. In making our choice of qualities we shall not demand, there- 
fore, those most difficult of attainment, but those most desirable in 
themselves. We can afterward inquire if the most desirable qualities 
are more or less difficult to realize; this will be merely an accessory 
matter. 
We are therefore called upon to pass judgment upon the practical 
advantages in types of air-ships. The first consideration is not to lose 
sight of the conditions under which by definition itself an air-ship is 
operated, conditions different from those which a boat or a railway 
train meets; no one can justly make an estimate of such dissimilar 
devices without recognizing the fundamental conditions of their 
utilization; that is, the nature of the supporting medium in which 
they move, the earth, water, or air. 
Locomotion on land brings into touch all the habitable places on 
the earth except those separated from each other by expanses of 
water impossible to bridge. But with this advantage there is still 
an element of great disadvantage. To attain on land perfect condi- 
tions for speed and carrying power, it has not been enough merely 
to train animals or create powerful and ingenious machines. These 
achievements would not have counted for much unless the route had 
been prepared by the construction of roadways, involving an enor- 
mous amount of labor and money. Without highways and railways, 
automobiles and locomotives would be powerless. This is so true at 
the present day that the importance and the perfection of the ways 
of communication are considered the principal criteria of material 
civilization, and where these means are lacking we are no further 
advanced than were those of the days of Joshua. 
A water transportation line, and herein lies its inferiority, only 
admits of the joining together of a very limited number of places, 
those along the shores of seas or along navigable streams. There is, 
however, the enormous advantage of not requiring a preliminary 
preparation of roadways. To travel by water, with all the perfec- 
tion possible to obtain, it is only necessary to have good ships. The 
sea has at all times been the chief means of communication between 
the various countries of the globe; all the ocean shores have been 
fairly well known for a long period, while there have remained im- 
mense tracts of country unexplored in the interior of the continents. 
If to venture an hypothesis, there existed in the center of Africa, 
or in the midst of the deserts of Asia, an unknown but populous city, 
the center of a flourishing civilization, the explorers who had dis- 
covered it could tell of its marvels on their return, but this newly 
discovered city would still remain apart from general civilization 
simply because it was not connected with other countries by per- 
