ter, add 1 gallon of pine tar, and
stir thoroughly with a wooden paddle until the mixture, which at first
looks streaked and muddy, brightens to a uniform, thick fluid somewhat
resembling molasses. Test it by letting about a teaspoonful drip from the
paddle into a glass of water (a glass fruit jar or a wide-mouth bottle
will do) and stirring thoroughly with a sliver of wood. It should mix
perfectly with the water. Globules of tar which can be seen by looking at
the glass from underneath and which can not be blended with the water by
repeated stirring indicate that more caustic-soda solution is needed. In
that case make up more caustic-soda solution of the same strength and add
it, not more than a pint at a time, with thorough stirring, until the
desired effect is produced.
If an appropriate glass vessel for making the test is not at hand, take a
little of the mixture between the fingers, then dip the fingers under water
and try to rub off the tar. It should leave the fingers perfectly clean
after a little rubbing with water. If an oily coating remains, more
caustic-soda solution is needed. Such an extra addition of caustic soda
will be required only in case of a very low-grade chemical or a very highly
acid tar. The tar stock should be kept in closed containers, such as a pail
with a friction top.
The quantity of S-B arsenic stock or of tar stock made in one operation can
be varied as desired, provided the above-given proportions of the
ingredients are adhered to. But one should attempt to work the S-B formula
on a larger scale only after skill and experience have been acquired.
_The boiled dip_ is less convenient than the S-B dip, but the final
composition and effect of dipping baths prepared from the two are the same.
To make a 500-gallon bath provide:
Sal-soda crystals 24 pounds.
White arsenic 8 pounds.
Pine tar 1 gallon.
Put 25 gallons of water into a kettle or tank of from 40 to 50 gallons'
capacity, heat to boiling, and add the sal soda. When this has dissolved
add the white arsenic, then boil and stir for 15 minutes or longer, until
the white arsenic has entirely disappeared. If intended for immediate use
cool to 140 deg. F. (by addition of cold water if desired), then pour in the
pine tar in a thin stream while constantly and vigorously stirring the
solution. Immediately empty the liquid into the dipping vat, which has
already been three-fou
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