(b) Stocks should be stored in a detached building which should not be damp. Jars or cases should not stand on a wooden floor if possible.
(c) See ([d]) above.
Buying Sulphuric Acid.—(a) Commercial acid of specific gravity 1·84 is the best of its kind. It contains impurities which are non-injurious to rubber preparation.
(b) It is always advisable, if possible, to buy the acid in small jars containing not more than 100 lbs. each. Smaller jars, with a content not exceeding 50 lbs., would be preferable.
(c) If the acid is bought in jars, it should be stipulated that the stoppers be covered with a plaster head, and that the containing crate or case should have prominent labels or marks indicating the top of the case.
Formula for Use of Sulphuric Acid.—It will be understood that as this formula has been calculated for working with latex, having a consistency of 11⁄2 lbs. dry rubber per gallon, it applies in a strict degree only to such latex. In other cases, where the dilution of the latex is not known, the formula will serve as a basis for experiment until the correct quantity has been discovered.
(Sulphuric acid of specific gravity 1·84.)
Note.—The directions must be followed carefully, and glass measuring vessels should be used if procurable.
(a) Measure out 1 pint of strong acid, and pour it carefully and slowly down the inner surface of a jar containing 20 gallons of water. Do not pour it directly into the water.
The heavy acid will sink to the bottom of the jar, and a good mixture must be obtained by stirring well.