Popular Science Moiillih/ 



25 



rcquirt'iiK'nts are a riKxlcratfly large, 

 level space, a gas-main several inrhes in 

 diameter, a cartload of sand, two dozen 

 sandbags (eight by sixteen inches, with 

 four one-foot cords collected in a hook 

 around their open end), and plenty of 

 strong men wlio aren't afraiil to hold on 

 to the bag. 



The outer part of the empty rolled 

 gas-bag is the short hose, called 

 appendix, at the balloon's lower 

 end. A short cylinder of equal 

 diameter is slipped into its end, and 

 a longer hose of balloon cloth is 

 stripped over both and securely 

 tied around them. The other end 

 of the hose is similarly tied to the 

 outlet of the gas-main, whereujjon the 

 bag is unrolled and spread around the 

 appendix as the center. The seam of the 

 round opening on top of the bag is tightly 

 screwed into the circumference of the 

 valve. The seam of the similar opening 

 in the net is buckled to the same margin 

 by a circle of short straps. The net is 

 spread in the same manner, and a wide 

 circle of sandbags, previously filled, is 

 built around the spread bag and net 

 and hooked into the meshes. 



How the Balloon is Inflated 

 Once the gas is turned on it dilates 

 the hose with a roaring sound, rush- 

 ing into the balloon and raising the 

 center of the spread. You have the 

 impression that the gas which finds it so 

 hard to puff out the cloth could never 

 lift a man, but you do not realize the 

 physical fact that the buoyancy is 

 increasing continually with the addition- 

 al space occupied by gas. Soon the 

 meshes of the net begin to pull the bag 

 hooks, and since the circle occupied by 

 the spread 



Q 



FIG 8 



lain out of a circle of cloth. E\'en after 



the buoyancy increases the sandbags 



lash it firmly, for their total weight is far 



greater than the maximum lift, and their 



indixidual weight oxercomes (he fraction 



of lilt e.xerted by the mesh to which each 



is hooked. As the f)ags narrow in on the 



net they crowd together. Finally they 



reach the lowest meshes and are lifted 



from the ground by the attendants. 



Then the fully inflated balloon, 



now permitted to rise sufficiently 



to untie the hose from the appendix, 



is led to the basket nearby. 



The ends of the ropes into which 

 j^ the net issues are hooked by loops 



to the "collecting ring" above the 

 basket, and the hooks are now released 

 from the meshes and put over the ropes. 

 By sliding them slowly in toward the 

 basket the balloon is allowed to rise to 

 its normal position above the basket by 

 finally hooking clusters of bags around 

 the lower ends of the stout basket-ropes. 

 After a few details have been attended to, 

 such as tying the appendix with a knot, 

 which can be jerked open while ascend- 

 ing, and arranging valve, rip-cords; 

 ballast-bags and instruments, the passen- 

 gers climb in. 



The Start of an Ascension 

 The wind soon pulls the basket "off 

 its feet" and there is considerable 

 bumping and scraping, during which it 

 is a convenient thing for those inside to 

 have an "upper berth." Following this 

 comes the ticklish process of tentatively 

 taking off sandbags until the lift is 

 supposedly equal to the load and of 

 li'tting the raised basket go for a 

 moment to see whether it will fall or 

 rise. When the final "let go" is given 



the excitement 

 begins. 



During the 

 first moments 

 of rising there 

 is that f|ueer 

 sensation of 

 riding in an 

 endless eleva- 

 tor or Ferris- 

 wheel. Soon 

 this is forgot- 

 ten in a world 

 of silence. 



An air-tight attachment must be made between 

 the gas hose and the appendix 



