No definite system was used for testing the tincturing and spreading powers of the pigments, or for testing their permanence.

They push on under the hail of arrows to which they can make no reply, and try to save their unvisored faces by charging blindly heads down.

Ruzicka and his co-workers showed that the hydrocarbon irene, obtained on reduction of irone with red phosphorus/iodine, had the structure shown and this was confirmed by synthesis …

One can prepare the organo-rare earth complexes by rather easy bucket chemistry.