.CHAP. V.] 



BALLOONS. 



97 



of 500 metres ; then, throwing out ballast, they again rise 100 ; then 

 afterwards another descent of 500 m , then another rise, and so on, until 

 the earth is reached, which an experienced aeronaut can do with 

 the greatest precision, and without any accident whatever." 



When the descent is final, and for some reason or other the journey 

 is ended, the aeronaut, wishing to reach the ground, sometimes uses a 



FIG. CO. Valve of the balloon h lo'.e, nonl 



cord (guide-rope) furnished with knots, which falls below the car and 

 is fifty metres in length ; by degrees, as a greater quantity of this new 

 kind of ballast touches the ground, the weight carried by the car is 

 diminished, which gives it a tendency to rise again. The rapidity 

 of its fall is thus reduced. Lastly, one or two anchors may be used to 

 hook on to projections on the earth, trees, bushes, rocks, &.C., and to 

 stop the balloon finally in its course. The utility of these various 



H 



