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RUM

An alcoholic drink of characteristic odour, distilled from fermented molasses in the West Indies, and ordinarily containing about 48 per cent, alcohol.

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RICINOLEIC ACID

COOHThe glyceride of this fatty acid makes up some 80 per cent, of castor oil, and occurs also in curcas oil. It is yellowish, thick, solidities at 15 degrees C., has a sp. gr. of 0945 > soluble in alcohol, ether, etc., and is used in soapmaking, the manufacture of Turkeyred oils, and dressing of textiles.

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ROSANILINES

The animated bases of fuchsine or magenta dyes. The rosanilines are colourless, crystalline compounds, and only form dyes when united with an acid. Rosaniline and pararosaniline are obtained by precipitation of their salts with alkalies. The actual dyes are the salts of these compounds, and include magenta, otherwise known as fuchsine, rosaline nitrate , rosaniline acetate , and parafuchsiue. These all dye wool and silk without a mordant, giving a magnificent fuchsinered colour in solution, but are themselves in crystalline form, of a bright metallic green lustre. They are soluble in hot water and alcohol. Rosaniline yields rosolic acid by treatment with nitrous acid. The formulae of rosaniline and pararosaniline may be shown as below:

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RHEOSTATS

Instruments for regulating the flow of electric currents and for measurements, thus affording the means of controlling the amount according to Ohm

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RHUBARB

, the dried rhizome of Rheum officinale, of which many species grow wild on the high lands of Central Asia, and many are cultivated; used for its purgative properties. The juice of the stems contains oxalic, malic, and citric: acids. The root of rhubarb contains chrysophanic acid and other substances. English garden varieties are used as food.

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RESINITE

is the name of a sort of resin made by the action of formaldehyde upon phenol.

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REAGENTS

Solutions of various chemicals used for testing purposes in qualitative analysis. They comprise strong hydrochloric, nitric, and sulphuric acids dilute solutions of the same acids and various salts containing about 5 per cent, of the respective substancesthat is to say, 5 grammes by weight per 100 c.c. dissolved in water. For use in the practice of volumetric analyses, solutions of known strength, or socalled “standard solutions,” are employed, the quantities of the constituents bearing the same relation to each other as the numbers which express their chemical equivalents. When they are made of such strengths. that a litre contains equivalent weights in grammesfor example, 365 grammes in 1,000 c.c.they are termed “normal standard solutions.”

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REGELATION

The treezing of watei anew, brought about by the reduction of pressure, the meltingpoint of ice being affected by the alteration of pressure to a slight extent.

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RUSTLESS STEEL

A chromiumiron alloy, containing from 12 to 15 per cent, chromium, ard not more than 045 per cent, of carbon, now largely used tor the manufacture of cutlery, turbine blades, acid pumps, and exhaust valves for aircraft engines. It is not dissolved by strong or weak nitric acid, nor attacked by ammonia, but sulphuric and hydrochloric acids attack it readily.

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REDONDA PHOSPHATES

Natural phosphates of iron and aluminium found in the Islands of Redonda and Alta Vela.

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