245 reported on the synthesis of linear but alsobranched polymers prepared by di-, tri-, and tetra-alkyne andazide monomers like the combination of tripropargylamine(B 3)and(dihydroxymethyl)(diazidomethyl)amine(A 2)(com-pare the general outline in Scheme 17).
When discussing mineral formations in caves, we often talk about stalactites and stalagmites. A stalactite is an icicle-shaped formation that hangs from the ceiling of a cave, and is produced by precipitation of minerals from water dripping through the cave ceiling. Most stalactites have pointed tips.
A meteor is a streak of light in the sky made by a fast-moving piece of rock from Space, called a meteoroid, heating up and vaporizing as it hits the atmosphere. If any of the rock reaches the ground without vaporizing, what remains is called a meteorite. From the collection of Simon Camm, Cornwall County, England.