Water-proof And Fire-proof Cement For Roofs Of Houses
Slack Stone
Lime in a large tub or barrel with boiling water, covering the tub or
barrel to keep in the steam. When thus slacked pass six quarts through
a fine sieve. It will then be in a state of fine flour. To this add one
quart Rock Salt and one gallon of Water. Boil the mixture and skim it
clean. To every five gallons of this skimmed mixture add one pound of
Alum and one-half pound Copperas; by slow degrees add three-fourths
pound Potash and four quarts fine Sand or Wood Ashes sifted. Both of
the above will admit of any coloring you please. It looks better than
paint and is as durable as slate.