218 GOLDFISH VARIETIES AND 
itself within a few days, but, as elsewhere directed, it can nearly always 
be stopped by making the water very muddy. The particles of dirt get 
into the leak and choke it up. 
Aquarium Cements. The prime requisites of an aquarium cement 
are resistence to water, adhesiveness, moderately quick setting without 
ever becoming stone-hard, and being non-poisonous. A cement com- 
bining these qualities is composed of one pound of litharge, one pound of 
Plaster of Paris, two ounces of powdered resin and one-half pound of 
glazier’s sand; mixed with boiled linseed oil to a consistency of putty suit- 
able for glazing. This cement has been found to be good for both fresh 
and marine water aquaria. A durable cement for those who cannot 
obtain very fine sand is made of equal parts by weight of zinc white, 
whiting and litharge, mixed with boiled linseed oil to a firm but tacky 
consistency. 
CEMENT FOR Marine Aguarra. A cement used for large, city 
marine aquaria is composed of 3 parts by measurement of Portland 
Cement, 3 parts fine white sand, 1 part powdered resin; mixed with 
boiled linseed oil. 
CEMENT FOR WoopEN-FRaAMED AQguaRIA. The best cement for 
small wooden-framed aquaria is made of 1 part of gutta percha and 4 
parts of pitch, boiled together and applied warm, first heating the glass 
somewhat. It is difficult to handle this quickly enough on large aquaria, 
for which the following will be found better: 3 parts Portland Cement, 
2 parts zinc white, 3 parts fine sand, 1 part powdered resin, made into a 
firm paste with boiled linseed oil. 
CONCRETE AQUARIA 
The making of concrete aquaria opens a new and an unlimited field. 
Those who have felt that the metal-frame aquarium is hopelessly restricted 
and commonplace can here find more room for individual expression, 
design and achievement. The illustration facing title page gives an idea of 
possibilities along this line. The aquarium shown is one designed and 
built by Mr. L. M. Dorsey and probably represents the highest develop- 
ment, up to this time, of artistic ideas as applied to a household aquarium. 
In the Philadelphia Aquarium Society annual competition Mr. Dorsey 
was awarded the prize cup three times, thereby becoming its permanent 
possessor. 
As individual ideas will vary so widely in the design of concrete 
aquaria, only a few (yet important) directions can be given. Cement 
should be of the highest grade, fresh and free from lumps. A mixture 
of one part cement to two of clean, sharp sand is about right. Wooden 
