66 THE GOLDFISH AND ITS CULTURE, 
color, bizarre in shape, no two pieces alike, and light in 
weight. I introduced tuffstone for the purpose it is now used 
for first, in 1874. To cement broken pieces or to form rock- 
work for an aquarium, use equal parts of best Portland cement 
and sharp sand. It should be soaked in water over night 
before it is placed in an aquarium. 
