"The wings and fuselage are both filled," said Paul; "that is what makes the Sky-Bird so light.  If you had brought more helium the last time you were here, I could have pumped in twice the quantity, I think, and that would have made her so light she would rise of her own accord, I really believe.  As it is, she now weighs less than a half-ounce.  I had the scales on her yesterday."