External characters

Of special importance is the odour, which may be conveniently judged by rubbing a few drops of the oil between the hands or by moistening with it a strip of filter-paper or a piece of cotton-wool. 

This is measured in the usual way, i.e.,with a Westphal balance or picnometer, generally at 150 C. If only a small quantity of material is available, use may be made of a small U-shaped picnometer (see Spirits, p. 233). If a temperature other than 150 is used, the result may be corrected by means of the coefficient o 00075, to be added for each degree above, or subtracted for each degree below, 150 C. 

The specific gravity of any oil is not, however, constant but is influenced by the development of the original plants, the method of preparation or purification of the oil, its age, etc. 

If no polarimeter is available, use may be made of a saccharimeter with a Ventzke scale, the different dispersive power of the quartz with respect to essences being disregarded. In this case the saccharimetric divisions are divided by 2-89 to obtain circular degrees. A tube 10, 5 or 2-5 cm, long is used according to the rotatory power of the ofl. 

The rotatory powers of. some essential oils vary within fairly wide limits. Tins measurement should, however, never be omitted, since it is of great use III the detection of adnltrratmn, esper mlly with oils of voiy high rotatory powers, such as lemon and orange oils. 

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Pocock R. (1916). On the external characters of the Mongooses. Proc Zool Soc Lond 1916, 349-374. 

It may be remarked here that the presence of silvor, notwithstanding the proportion may be so large as the one-fifth of the whole, does not materially alter tho external characters of the galena hut when silver is present iu that amount, other metals, such as antimony and bismuth, are also contained in the minoral in appreciable quantities. The richest silver-lead ore. is that found at Tamowitz in Silesia, which contains about a fifth of its whole weight of silver the usual proportion of this metal is, however, from 0.0001 to 0 003 per cent., and tho ore is designated by the Germans Weiegulligerz. 

With these the analysis has the same object as with sausages and meat extracts, namely, the determination of the nutritive value and the detection of any adulteration or change. The determinations made, either separatdy on the liquid and meat or on the product as it stands, are those of the water, ash, fat, nitrogen, aridity of the fat, horseflesh, starch, colouring matters and antiseptics, the methods given under sausages being followed. In this case special importance" attaches also to the examination of the external characters of the tin and to the test for metals. 

It is usually sold under the name margarine, and it has the appearance and consistency of ordinary butter and pleasing external characters, but with practice it is readily distinguishable from real butter. 

External Characters.—The cheese is struck with the knuckle or with a small hammer on the rind to ascertain if it gives a clear, sharp sound (sound cheese) or if there is discontinuity (blisters, honey-combing, fissures). The interior is examined to ascertain if this is homogeneous, and in the case of a cheese with cavities, if these are uniform to determine if the odour is agreeable and piquant (sound cheese) or repulsive (altered), if the taste is that characteristic of the particular cheese and if the colour is uniform or if red, black or bluish spots are present. 

The external characters (colour, odour, elasticity and tenacity) of the gluten indicate its quality and so the behaviour of the flour as regards bread-making. 

Special apparatus may be used by means of which the swelling power of the gluten on heating is determined, but the indications thus obtained are in no way more valuable than those of a qualitative study of the external characters. 

The acidity, ash, external characters, colour and gluten furnish the best data for valuing flour. 

External Characters.—The taste and smell—whether pleasant or not, add, etc.—are observed. The crumb is also examined to ascertain if it is soft, porous, elastic, homogeneous and adherent to the crust, a lens being used to see if coloured spots or traces of mould occur in it, if it is more or less white, and if the fragments of bran present are more or less numerous. 

External Characters.—The taste and smell are noted to ascertain if there is any rancidity or mouldiness also the colour whether yellowish, whitish or grey the outer appearance whether uniform or otherwise the appearance of the fracture whether vitreous or floury. No trace of mould or parasites should be observable, either by the naked eye or with the aid of a lens. 

External Characters.—The colour, odour and taste are to be noted. White or yellow dextrins are mostly prepared by means of acid (hydrochloric acid tends to give a reddish and nitric acid a greyish tint), whereas brown dextrins are those obtained by direct torrefaction without acid. 

External Characters.—Note is made especially of the colour, consistency, homogeneity, odour and taste of the product with practice, useful conclusions with regard to the quality can then be drawn. 

External Characters —Honey may be white (centrifuged honey) or brown (coniferous honey), or pale yellow, yellow, dark yellow, greenish yellow or reddish, and its taste should be more or less markedly sweet with an almost imperceptible bitter sensation (due to small proportions of malic... 

External characters Semi-liquid, viscous syrup, white to yellow to brown, taste sweet and aroma characteristic. 

Examination of beer includes, in addition to observation of its external characters (smell, taste, colour, clearness, formation and retention of froth or head ), determinations of the essential components and of any substances formed by alteration of the beer itself or added as adulterants. 

It is not-usually necessary to determine the carbon dioxide in beer, since the external characters of the latter generally indicate if the gas is present in sufficient quantity. When, however, the determination is necessary, loss of gas during the extraction of the beer must be avoided. To this end, the vessels may be well cooled before they are opened, or special automatic extraction apparatus may be employed by means of which the beer is transferred directly, without loss of carbon dioxide, from the cask or bottle to the flask used in the determination. 

The external characters, namely, the colour, brilliancy, smell and taste, are noted as soon as the bottle is opened, the most suitable temperature being 150 C. for white wines and 170 for red ones. If carbon dioxide is... 

External Characters Specific Gravity Rotatory Power Solubility in 90% and 80% Alcohol.—These determinations are made as described under General Methods. 

External characters The genuine oil has normal colour and smell Large additions of terpenes weaken the colour oil extracted mechanically is more coloured than that pressed by hand... 

External Characters.— The colour, clearness and smell are noted. A yellowish colour indicates a poorly rectified or old or adulterated product (especially one containing crude pine oil). Turbidity or opalescence indicates the presence of suspended impurities, particularly water. The smell, which is well observed by rubbing a little of the oil between the hands, may indicate the presence of mineral or tar oils, etc. 

Examination of colophony comprises firstly observation of the external characters (colour, transparency, fracture) and comparison of these with those of commercial grades of known origin determinations 1-6 may also be carried out to ascertain the degree of purity. Lastly, in order to discoverif a product is really colophony and not some similar product such as brewers pitch, Burgundy pitch, resinates, mixtures of colophony with resinates or with resin oils, fatty oils, etc., tests 7-10 may be carried out. 

When not powdered, the raw materials may usually be distinguished by their external characters. With powdered materials, the microscopic comparison with genuine products often gives useful indications.1... 

These include, besides examination of the external characters, determinations of the specific gravity, strength and permeability, and sometimes microscopical investigation. 

External Characters.—The appearance of the surface of the leather is examined on hoth faces—the smoothness, grain, colour, presence of spots, cuts, holes or other defects. The leather is bent on itself to ascertain if it cracks and breaks or remains unaltered. 

Extraneous Organic Substances.—To detect glycerine and dextrin, the substance is mixed with water, the insoluble matter allowed to settle, the liquid filtered, the filtrate evaporated and the residue examined as to its external characters, polarisation, behaviour when heated, etc. Starch is detected microscopically, and fatty oils by extracting the substance with ether and examining the ethereal extract. 

Appearance an External Characters. These indude the colour, smell, purity, degree of softness and uniformity of the sample, the presence of any obvious defects of treatment (spots, etc.). 

This consists simply of a convex lens or several combined into a system and appropriately mounted. A good example of a simple microscope is a reading glass. This type of simple microscope is valuable in field work, in the examination of dried herbarium material or the external characters of crude drugs, where only a low magnification of the object is required. 

There are three translational dispersion curves and three rotational dispersion curves. In the absence of rotation-translation coupling these vibrations are also distinctly separate. However, external modes and internal modes of the same character will become mixed, the closer they are in frequency the greater will be the mixing. Atomic displacements are no longer controlled by exclusively internal or external forces but by both. Modes of a mostly internal (or mostly external) character now involve displacements of the centre of mass (or deformations of the molecular frame). This is a general feature of all molecular crystals but it is usual to ignore such complications when the frequency of the lowest... 

With bases, for which it has great affinity, selenic acid forms salts, called seleniates, which are isomorphous with the corresponding sulphates, and entirely resemble them in external characters. 

The solution of caustic soda, owing to the superior purity of the carbonate, which is generally free from sulphate and chloride, is much purer than the common aqua potassse and when boiled down, it leaves a very pure hydrate of soda, NaO, HO. This hydrate is, in all external characters, and in most chemical ones, exactly similar to caustic potash it is deliquescent and caustic, and may be used for almost all the same purposes. The solution, however, cannot be used for organic analysis, as it froths up like solution of soap when a gas passes through it. 

Each bond has simultaneously both internal and external character. 

The monosubstituted [18]annulenes have less conformational mobilit than [18]annulene itself [36,52,55]. The variable temperature n.m.r. shows an interesting pattern in that warming of a solution results in a coalescence of the signals for all the internal protons and same of the outer protons. Other outer protons retain their distinctive external character throughout. The explanation derives from the fact that three equivalent conformations are possible each with six internal and twelve external protons. If a substituent is present which cannot, because of its size, occupy an internal position, then five protons, at the 4, 7, 10, 13 and 16-positions are also prevented from occupying internal positions, and so retain the character of external protons unchanged over the temperature range [52]. 

It should be emphasized that perturbation may not necessarily be of an external character, since molecular fluctuations may lead to. small spontaneous deviations of the system parameters from their mean values (Prigogine and Defay, 1954). 

Polyglyceryl esters are made from polyglycerol and fatty acids. They are more external than GMS, and their external character increases as the degree of polymerization and esterification increases. An increasingly important characteristic of both GMS and polyglyceryl esters is their low toxicity. Most are actually approved in the USA as food additives. 

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