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HYDR

ening a mixture of bromine and phosphorus, and exposing it to agentle heat.Soluble very readily in water, and the solution is decomposed instantlyby chlorine, and more slowly by nitric acid, which forms nitro-hydro-bromic acid, similar to aqua regia, and capable of dissolving gold.

Hydrociilorates arc salts formerly termed muriates.

Hydrochloratb of Brucia. This crystallizes in four-sided prisms,and is composed of 5 92 of hydrochloric acid, and 94-04 of brucia.

Hydrochloric Acid. See Acidum Muriaticum.

Hydrochloric ./Ether. See ./Ether Hydrochl.

Hydrocroconic Acid. This is procured from croconate of potass.(Gjielin.)

Hydrocyanate of Iron. See Ferrocyanate.

Hydrocyanate of Potass. New. Is prepared by exposing ferrocyanateof potass to long-continued heat, which will form a mass of cyanuretof potassium boiled with iron and charcoal, which are precipitatedby solution in water, and the hydrocyanate of potass is formed in aperfectly colourless solution. Or, cyanuret of potassium dissolved ineight times its weight of distilled water forms the medicinal hydro-cyanate of potass, which is used in the same doses (with more uni-form certainty of its strength) as the hydrocyanic or prussic acid.See Acid. Hydrocyanicum.Poisonous. The 100th part of a grain of the first preparation caused acock linnet to drop dead in half a minute: ^ss killed a large dog inhalf an hour. The best treatment consists in exhibiting strong sti-mulants, such as hot brandy and water, &c, as quickly as possible.Test. Solution of sulphate of iron will give a brown precipitate, whichwill change to a bluish-green with sulphuric acid, and will graduallydeepen into a full blue.

Hydrocyanic Acid. See Acidum Hyrocyanicum.

Hydrofluoric Acid is prepared by acting on fluor spar finely pul-verized and free from siliceous earth, with twice its weight of con-centrated sulphuric acid.It acts strongly on living animal substances, and if a drop the size ofa pin's head of the concentrated acid come in contact with the skinit produces a deep malignant ulcer. The vapour is also deleterious.

Hydrolapathum. O. The Water Dock. Rumex aquatica. A nativeplant, but not common. The powder of the root is used as a den-tifrice, and the infusion as a wash for putrid spongy gums. It isalso said to be useful in chronic rheumatism and visceral obstructions;but is only used by herbalists.

Hydromel, or Metheglin. A liquor formerly in great repute, made byputting Ibxxviij of honey into a nine-gallon cask, with as much boil-