This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
By boiling arsenious acid with hydrochloric acid and distilled water, preserving a proportion of 4 gr. to 1 oz. (This solution corresponds in strength with liquor arsenicalis; it is nearly three times the strength of liquor arsenici chloridi, London, and of the original acid solution of De Valangin.)
A colorless liquid of acid reaction and sp. gr. 1.009.