The record of pharmacy and therapeutics (part second) : being an account of improved pharmaceutical preparations, recently-introduced remedies, and a catalogue of unadulterated drugs and chemicals of the General Apothecaries' Company, (Limited), 49, Berners Street, Oxford Street, London.

  • General Apothecaries Company (London, England)
Date:
1857
Catalogue details

Licence: Public Domain Mark

Credit: The record of pharmacy and therapeutics (part second) : being an account of improved pharmaceutical preparations, recently-introduced remedies, and a catalogue of unadulterated drugs and chemicals of the General Apothecaries' Company, (Limited), 49, Berners Street, Oxford Street, London. Source: Wellcome Collection.

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    the metal. He considers the action of these waters on lead to be due to the quantity of air dissolved in them. More recently, at the request of the Government, Professors Graham, Hofmann, and Miller undertook the investigation of the action of waters on lead, and in reply to the question— “ whether any comparative inconvenience would arise from a supply of soft water to the Metropolis,’’ they allude to the supposed danger and liability of soft waters acting upon and dissolving lead; but in opposition to the prevailing opinion that soft waters always act upon lead, they mention that, with one exception, neither the soft waters of the Surrey Hills, which have a hardness of only 2 degrees, nor spring- water artificially softened to 3 degrees of hardness, have any perceptible action on lead. The idea that soft waters invari¬ ably act upon lead, seems to have its origin in the fact that certain specimens of distilled water, placed in contact with a large surface of bright sheet lead, dissolve as much as 6 or 8 grains of the metal to the gallon. Prom certain observations made while conducting researches on the nature of the organic matters contained in the waters supplied to the Metropolis, I was induced to institute some experiments on the action of certain constituents of waters on leaden pipes, with the view of setting the question at rest. A gallon of the distilled water used in my laboratory, placed in contact with 560 square inches of sheet lead, dissolved, in 48 hours, 6.5 grains of lead, which was found at the bottom of the bottle in the shape of white insoluble carbonate, not more than one-sixtieth of a grain remaining in solution. Numerous experiments on the waters of London have enabled me to establish the important and interesting fact that the nitrogen of sewage and other organic matter is, under certain influences, readily converted, first into ammonia and, by the same influences, part of the ammonia is oxidised and converted into nitrous acid, which combines with ammonia and is found in the water as nitrite of ammonia. The presence of nitrite of ammonia in water I have clearly established by the most conclusive experiments, and it is to the presence of this sub¬ stance, both in distilled waters and waters selected for domestic use, that the action of such waters on lead is due. The nitrous acid attacks the lead and forms the soluble nitrite of lead, which by exposure to air combines with car¬ bonic acid and precipitates the oxide of lead in the form of insoluble carbonate of lead, setting free the nitrous acid again to attack and dissolve a fresh portion of lead. On testing ordinary distilled water (distilled from Thames