Fig. 8. — Bubbles of Ammonium Oleate, 3 per cent, in 

 30 PER CENT. Glycerine. Thinned to first green. 





Fig. 9. — Bubbles of Potassium Oleate, 5 per ci-,nt. in 

 50 PER CP2NT. Glycerine. Air pressure over 1 mm. Hg. 



