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FULMINATING MERCURY or FULMIN A.TE OF MERCURY

A dark brown, crystalline compound used for priming percussion caps and in making detonators. It explodes when dry under the slightest friction and has to be kept wet until used. It is prepared by the action of strong nitric acid upon mercury and alcohol.

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FLASKS

are glass vessels of varying shapes for holding liquids, consisting of a body part with flattened bottom, and a neck which can be easily grasped by the hand or held by a clamp, and closed with a cork when required. The glass of which they are made is of a quality to permit the contents to be heated to the temperature of boiling water. Erlenmeyer FlankA glass flask of the “conical” type, having a flat bottom of diameter equal to from half to threequarters of its height, and with side surface tapering smoothly from that base to the bottom of the neck, which is short, narrow, and straightsided. These flasks have the advantage of being more easily washed out than round flasks, but they are somewhat more liable to crack on heating.

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FUCHSINE

Another name for magenta, one of the aniline dyes used in the textile and leather industries.

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FIREWORKS

are luminous devices made from combustible or explosive chemicals, largely dependent upon the use of gunpowder, metallic filings being introduced to produce scintillation, and many chemicals bemg used in association, to produce colouring and other effects.

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FULLLER

A natural porous and absorptive aluminium silicate, of greyish, yellowish, or greenish colour, widely distributed and largely produced both in England and in the United Statesa powerful absorbent of oily matters. At one time it was extensively used for “fulling” clothes, but now it is chiefly employed in connection with the bleaching and filtering of fats and oils, as a carrier of pigments, the removal of grease from woollen goods, and as a toilet article. The English supply ot Fuller

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FERRUGINOUS

Containing iron. Many natural mineral waters are more or less ferruginous in character and act as tonics.

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FLASHPOINT

is the temperature at which an oil or other combustible fluid gives off vapour which will then fire if exposed to a naked light. The appliance used in this country for determining flashpoints is one known as Abel

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FORMALDEHYDE or METHYL ALDEHYDE

is a gas soluble in water, and a solution of 40 per cent, strength is an article of commerce, largely used for disinfecting and preservative purposes. It has a very irritating action on the mucous membranes of the eyes, nose, and throat. It is made by a contact action brought about by passing a current of methyl alcohol vapour admixed with air over a glowing platinum or copper spiral, and absorption in water, in which solution it has the hydrate formula CH22. It possesses the property of making gelatine in any form insoluble in water, and this is utilized in many technical applications, including the preservation of adhesives and anatomical specimens. It is also used in the processes of making bakelite and other allied articles. The polymeric solid white paraform is more useful for disinfecting rooms by fumigation, as it is easily vaporized and is equally effective per unit of active agent. Formaldehyde is believed to play an important part in the process of plant assimilation.

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FRIT

The materials used in compounding glass and enamels as obtained by the baking or calcination of them, but before fusion.

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FERROCYANIDES

Compound cyanides of iron and other metals, of which potassium ferrocyanide is typical. They are produced from ferricyanides by the action of reducing agents, potassium feri icyamde, for example, yielding the ferrocyanide by the action of grape sugar in presence of potassium hydrate.

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