Lightness

Our planet moves in space with the lightness of a bird in flight.

Hand in hand, heaviness becomes lightness.

If it's too heavy, add lightness.

The butterflies appear to dance in the air, providing a feeling of lightness and freedom.

Sometimes in the course of our adventure we came upon worlds inhabited by intelligent beings, whose developed personality was an expression not of the single individual organism but of a group of organisms. In most cases this state of affairs had arisen through the necessity of combining intelligence with lightness of the individual body. A large planet, rather close to its sun, or swayed by a very large satellite, would be swept by great ocean tides. Vast areas of its surface would be periodically submerged and exposed. In such a world flight was very desirable, but owing to the strength of gravitation only a small creature, a relatively small mass of molecules, could fly. A brain large enough for complex "human" activity could not have been lifted. In such worlds the organic basis of intelligence was often a swarm of avian creatures no bigger than sparrows. A host of individual bodies were possessed together by a single individual mind of human rank. The body of this mind was multiple, but the mind itself was almost as firmly knit as the mind of a man. As flocks of dunlin or redshank stream and wheel and soar and quiver over our estuaries, so above the great tide-flooded cultivated regions of these worlds the animated clouds of avians maneuvered, each cloud a single center of consciousness.

But Mr. Duxbury says that despite its extraordinary lightness, aerogel can be quite sturdy.

There's a lightness in my heart after talking with him.

Well, darkness has a hunger that's insatiable and lightness has a call that's hard to hear.

The unique chassis design is largely the secret of the lightness of the locomotive.

In the lightness of my heart I sang catches of songs as my horse gayly bore me along the well-remembered road.