SUPERIORITY IN AN ATR-SHIP—-RENARD. 155 
portant quality, but the others can be obtained without modifying the 
construction in the slightest degree, and except for attaining altitude, 
without losing any velocity, but even gaining it, with an increase in 
the carrying capacity and in the qualities which are dependent on it. 
This is not the case with dirigibles. To be sure, with them as with 
aeroplanes, general perfection of apparatus—motor, propellers, forms 
of small resistance—is indispensable to velocity and can likewise 
exert a favorable influence on the carrying capacity and its resulting 
consequences, but another factor intervenes, the volume of the balloon. 
This exerts an enormous influence on the carrying capacity, which 
dwarfs that resulting from the general perfection of the apparatus. 
Although by increasing the individual velocity we can indirectly 
increase in a slight degree the carrying capacity, we possess, more- 
over, a means of increasing this quality absolutely independent of 
those which produce velocity. I may add that this method has no 
great merit in its application. It is not very difficult to add a few 
hundred cubic meters to a balloon, or even more. I would not go as 
far as to say that the problem is of extreme simplicity, but it is a 
small matter beside those that have to be solved in increasing the 
individual velocity of a dirigible. Consequently, as far as machines 
lighter than air are concerned, if from a utilitarian point of view 
the carrying capacity is an inferior quality, it is equally so from a 
technical standpoint, for it is much easier to attain than individual 
velocity. 
Thus there are in an air-ship only two fundamental qualities from 
which all the others are derived, individual velocity and carrying 
capacity; and from a practical standpoint the latter is much less im- 
portant than the former. 
In considering the difficulties to be overcome, in an aeroplane the 
question does not arise, for in such apparatus the qualities sought 
for are so involved one with the other that every added improvement 
allows of the increase according to choice of one or the other of the 
properties desired in an air-ship. With dirigibles this is not the case, 
for carrying capacity is much more easily obtained than individual 
velocity, and the technical considerations which are involved in ma- 
chines lighter than air are merely those that are basic in the utiliza- 
tion of an air-ship. 
Simply because a colossal dirigible has accomplished long journeys 
and covered great distances, the superiority of this type of air-ship 
over all others should not necessarily be proclaimed. The machine 
that should interest us most is the one capable of the greatest individ- 
ual velocity, and as this velocity is difficult to measure, we should 
estimate it from the absolute velocity attained in flying in a closed 
circuit in such a way as to eliminate from the final result, as much 
as possible, the effect of the wind. 
