Part 172
_Obs._ The ingredients in the above compounds are to be separately reduced to powder and sifted through lawn, after which they should be kept in well-corked wide-mouthed bottles until the time of mixing them for use. The chlorate of potassa, more especially, must be separately treated and cautiously handled, in order to prevent the possibility of explosion from friction whilst it is in contact with combustible matter. The requisite quantity of each of the ingredients being weighed out and placed on a clean sheet of white paper, the whole is to be thoroughly but carefully mixed together with a light hand, by means of a bone or wooden knife. The compound is next lightly packed into small cups or pans for illuminations, or into small pill-boxes for stars and trains, a little priming and quick-match being lastly attached to each. To ensure success the several ingredients must be dry and commercially pure; and though reduced to the state of a uniform powder, care must be taken that they are not absolutely 'dusty,' or too finely pulverised. The nitrate of strontia, alum, saltpetre, carbonate of soda, &c., before being weighed, require to be gently heated in an iron pot or pan until they fall to powder, and lose their hygrometric moisture, or water of crystallisation. To ensure the perfect admixture of the ingredients, the whole, after they have been stirred together on paper, as before directed, may be passed through a hair or perforated zinc or brass sieve. Further, as coloured fires rapidly deteriorate by keeping, and even sometimes inflame spontaneously, to prevent disappointment and accidents they should not be prepared long before they will be required for use, and should be stored in some situation in which their spontaneous combustion would be productive of no disastrous consequences.
Of the above formulæ, those bearing the name of the late Mr Marsh, of Woolwich, more especially deserve the attention of the pyrotechnist. To guard against the danger sometimes arising from the spontaneous combustion of coloured fires containing sulphur and chlorate of potash, Mr Saunders recommends intimately mixing 120 grains of bicarbonate of potash with each pound of sulphur before using it in the manufacture of any composition into which chlorates enter. See FLAME, PYROTECHNY, &c.
=FISH.= _Syn._ PISCES, L. Fishes form the _fourth class_ of vertebrate animals (VERTEBRATA) in the Cuvierian arrangement of the animal kingdom, and in the variety of their genera and species are second only to the INSECTA, whilst in prolificness and number they probably exceed all other animated beings that reach a size equal to that of even the smallest member of their prodigious race. Besides their value to man as food, they furnish him with oil, isinglass, and various other articles of utility and luxury, and provide, either directly or indirectly, an inexhaustible supply of manure for the fertilisation of his fields. As food fish are undoubtedly wholesome and nutritious, although less so than the flesh of animals or the grains of the cereals. Of all the various substances used as aliments by man, fish are, however, the most liable to run into a state of putrefaction, and should therefore be only eaten when perfectly fresh or, if not recently taken, then only when their perfect preservation has been ensured by any of the ordinary methods employed for the purpose. Those that are the whitest and most flaky when cooked, as cod, flounders, haddock, hake, soles, turbot, whiting, &c., are the most easily digested; and those abounding in oily matter, as eels, herrings, mackerel, salmon, &c., are most nutritious, though the most likely to offend the stomach. Salt-water fish have been said to be more wholesome than river fish, but without sufficient reason. Salted fish are hard of digestion, unless when carefully cooked and well masticated. Skin diseases are said to be more common among those who live continually on fish than among those who abstain from it; but this probably arises from their use being unaccompanied by a proper quantity of fresh vegetables or fruit, both of which are scarcer on the sea-coast than further inland. As one of the components of a mixed diet, the value of fish is indisputable. Acid sauces and pickles are the proper additions to fish, from their power of retarding the progress of putrefaction, and of correcting the relaxing tendency of large quantities of oil and butter.
_Artificial Propagation._ The fecundity of fish is positively marvellous. According to the recent observations of Mr Frank T. Buckland, salmon yield about 1000 ova or eggs to every lb. of their weight; a trout weighing 1 lb. produced upwards of 1000; a mackerel (1 lb.), 86,120; a herring (1/2 lb.), 19,840; a sole (1 lb.), 134,466; a turbot (8 lbs.), 385,200; and a cod (20 lbs.), 4,872,000. The ova here spoken of form what is commonly called the 'hard roe' of the female fish; the 'soft roe' is 'the milt' of the male fish. To protect the spawn, and the fry, when hatched, is the object of the art of fish culture, which has made great progress during late years. When the spawn is not artificially protected, the greater portion is always wasted, being swept away by the stream, and devoured by fish, birds, and insects. The natural enemies of the newly hatched fish are, again, so numerous, that it is really surprising that any should escape destruction. According to given data and accurate calculations of the returns of fisheries made by Messrs Ashworth and Buist, only one salmon egg out of every thousand deposited ever becomes a fish fit for human food. Other fish, both fresh and salt water, suffer in proportion. The hatching of fish by artificial means has been carried out on a large scale in France, and has been commenced in Scotland and Ireland, and on a small scale in England. The spawning fish, having been caught by a net, is made to deposit her eggs by gently pressing on the abdomen; these are impregnated by 'milt' expressed from the male fish in a similar manner, and mixed with them in a shallow tub or other vessel prepared for the purpose. The impregnated eggs are placed in long shallow boxes, bottomed with gravel and pebbles, and so arranged that a small stream of water from a reservoir may flow from one to another. The time of hatching depends entirely upon the temperature of the water; from 40° to 45° Fahr. seems to be the healthiest temperature. After about 50 days (in the case of salmon), when all goes well, the young fish makes its appearance as a misshapen creature about an inch long, with a bag containing the yolk of the egg attached to its abdomen. At 3 days old the fry is about 2 gr. in weight; at 16 months it has increased to 2 oz. To preserve the young fish in health, the boxes must be covered with shades of slate or zinc. The French fish-breeders generally feed the young fry with boiled frogs powdered fine. The Scotch give boiled liver. Mr Buckland prescribes a diet of roe of sole, or plaice, or whiting. As to the age at which it is advisable to turn the young fish out of the nursery, there is much difference of opinion. Some breeders recommend turning them out as soon as the 'umbilical bag' is absorbed; others think they should be taken care of till they are older and stronger, and better able to defend themselves or escape from attack. For full details respecting the artificial propagation of fish, the reader is referred to Mr Buckland's recent work, entitled 'Fish-Hatching.'
_Nutritive Value of Fish._--The white varieties of fish, such as _whiting_, _cod_, _haddock_, _sole_, _plaice_, _flounder_, and _turbot_, according to Letheby, contain only about twenty-two per cent. of solid matter, of which eighteen is nitrogenous. To increase their nutritive value, therefore, these fish should be eaten with butter.
According to the same authority _mackerel_, _eels_, and _salmon_ are richer in fat than the above kinds; mackerel containing about seven per cent., and salmon about six, whilst the oily matter of eels amount to nearly fourteen per cent. The same is the case with the _sprat_, the _herring_, and the _pilchard_, as well as with most of our fresh-water fish.
As regards _shell-fish_, all the different varieties of them afford about the same amount of nutrition. They contain about thirteen per cent. of solid matter, which in composition is similar to that of white fish. Shell-fish vary in digestibility; _mussels_, _limpets_, and _whelks_ being rather difficult of digestion, whilst _scallops_, _cockles_, _periwinkles_, _lobsters_, and _crabs_ are a trifle more easy of digestion, and _oysters_ still more so. All shell-fish are unsuited for delicate stomachs; although they are largely eaten by the poorer dwellers on the coast.
On the Continent, _vineyard snails_, and in China, _slugs_, are eaten, and are said to possess a delicate flavour and nutritive properties.[311]
[Footnote 311: Letheby.]
_Choice, &c._ "The flesh of any fish is always in the highest perfection, or in season, as it is called, during the period of the ripening of the milt and roe. After the fish has deposited the spawn, the flesh becomes soft, and loses a great deal of its peculiar flavour. This is owing to the disappearance of the oil or fat from the flesh, it having been expended in the function of reproduction." (Fleming's 'Phil. Zoology.') Fish should be dressed as soon after being caught as possible, as much of their peculiar delicacy and flavour is lost by keeping, even for a few hours. Turbot and salmon are said by the fishmongers to be improved in flavour when 2 or 3 days old, but this is surely a mistake, as the former, when dressed immediately after being caught, possesses a fine creamy taste, which it afterwards loses; whilst the latter, by the loss of a single tide, loses a portion of the fine white curd which is previously found between the flakes, and by longer keeping, this curd, with the larger flakes, disappear altogether. In the eyes of some epicures the richness, is however, increased by this change. Mackerel, and some other fish suffer so much from keeping only a few hours, that they become quite unwholesome. Herrings offer a remarkable example of the advantage of dressing fish as fresh as possible. When cooked soon after being caught, they possess considerable delicacy and flavour, but after being kept for only a few hours, the oil separates from the flesh, and they become soft, greasy, and strong-flavoured.
In the choice of every kind of fish, stiffness, brightness of the eyes, and redness of the gills, may be regarded as invariable signs of freshness. A peculiar elasticity will also be perceived in fish recently caught, little or no permanent impression being made by the ordinary pressure of the fingers, from the flesh immediately rising when the pressure is withdrawn. Fresh fish also lie in a partly curled position, and never quite straight, as in the case when they have been kept for some time. Thickness and fleshiness are deemed marks of the good condition of all fish.
_Cleaning, dressing, &c._ On the proper cleaning of fish preparatory to dressing it, depends much of its delicacy and flavour. Ordinary cooks seldom do this well, from not slitting the fish sufficiently open to permit the inside to be thoroughly washed, and seldom using sufficient water. The superior flavour of fish cleaned by the fishmongers arises from their performing the operation more completely, and from the large quantity of water they employ about them. The flavour of all fish is improved by adding a little salt or vinegar to the last water in which they are washed. The sound, milt, and roe, should be carefully cleaned and preserved.
Fish is preferably 'dressed' by simple boiling, broiling, or frying; in fact, the finer kinds of fish are often injured by the excessive interference of the cook. When boiled, "all large fish, with the skin whole, must be placed on the fire in cold water; if crimped, or cut into slices or pieces, in boiling water; if whole, it must not be covered with more than two or three inches of water, or the skin will crack, and not only spoil the appearance of the fish, but will diminish the gelatine and gluten it contains, and instead of eating firm and full of flavour, it will be soft and woolly, especially if over-boiled." (Soyer.) As soon as a scum rises from boiling, it should be removed by the skimmer. The addition of a little salt or vinegar to the water improves the flavour of most fish, and renders the flesh firmer. The proportions should be "two teaspoonfuls of salt to every quart of water." "If the fish be whole, as soon as it begins to boil remove the cover on one side, and let it simmer gently until done. (Soyer.) A fish is known to be sufficiently dressed by the flesh in the thicker parts separating easily from the bone. "If a large fish I generally try it by gently pushing a wooden skewer through the thickest part; if it goes in easily it is done." (Soyer.) When this is the case it should be removed from the kettle, as by soaking in the water fish loses its firmness, and becomes soddened. Sole, skate, and mackerel, are usually put into boiling water, whether whole or sliced. Fish for broiling should be well washed in strong vinegar, wiped dry with a towel, and floured before placing them on the gridiron; and the bars of the latter should be hot, and well buttered. (Rundell.) Fish for frying should be prepared as for broiling, and the butter, oil, or lard should be allowed to boil for a minute or two before putting them into the frying-pan. The latter should be perfectly smooth and bright, and the butter or oil in abundance, to prevent the fish sticking to it and burning. As the fish are cooked solely by the heat of the melted fat, to fry them in the highest perfection there should be enough of it to cover them. Butter or oil is the best for the purpose. To avoid loss, the contents of the frying-pan, after the fish is removed, should be poured into a clean jelly-jar or basin, and reserved for another occasion. The fish being removed from the pan, the superfluous fat should be drained from them preparatory to 'serving' them. When fish is divided into fillets or cutlets before being cooked, it is usual to take out the bones, and to dress it with force-meat, &c.
In serving fish of the finer kinds, no other additions are required than melted butter and the ordinary fish sauces and pickles. The dishes are commonly garnished with raw parsley, for the sake of appearance, but boiled parsley, chopped small, should accompany it. All kinds of fish should be served on a napkin.
_Caution._ It sometimes happens that a fishbone accidentally swallowed remains in the [oe]sophagus, and occasions serious inconvenience; in fact, instances have been known where so much irritation has arisen that death has followed. In such cases it is advisable, as soon as possible, to take of tartar emetic, 4 gr., dissolved in warm water, 1/2 pint; and immediately afterwards the whites of six eggs. The coagulated mass will not remain in the stomach more than two or three minutes, and the remedy has been known to "remove no less than 24 pins at once."
=FISH GLUE.= See GLUE and ISINGLASS.
=FISH POISONING.= See ACCIDENTS.
=FISH SKIN.= _Syn._ SHARK SKIN. The skin of the spotted dog-fish or rough hound (_chien de mer_, Fr.), stretched and dried. Used for polishing wood and ivory. Several other varieties of fish skin are employed in the arts. The dressed skin of the 'rousette' (_peau de rousette_, F.), is transparent, and very beautiful. Cemented on green paper, and rubbed down and polished, it is used as veneer for fancy boxes. The skins of several varieties of Squalus are also used for both the above purposes. See SHAGREEN.
=FIVE HERBS.= See SPECIES.
=FIX'ATURE= _Syn._ BANDOLINE, CLYSPHITIQUE, EAU COLLANTE, FIXATEUR, Fr. This consists of any of the simple vegetable mucilages, combined with a little spirit, to preserve it, and with a little perfume, to render it more agreeable.
_Prep._ 1. From carrageen, Irish, or pearl moss, soaked in cold water for an hour or two, and after being drained, and pressed dry in a clean napkin, dissolved by boiling in soft water, q. s. The decoction is strained through cambric, and when nearly cold is mixed with about 1/3rd or 1/4th of its volume of eau de Cologne or other scented spirit, with the further addition of a few drops (5 or 6) of oil of cloves. Sometimes a little brandy is added to the mucilage, and when it is intended for present use, as is common with home manufactures, the spirit is frequently omitted altogether. 1/4 oz. of the prepared moss is fully enough for 3/4 pint of strained decoction, if rightly managed.
2. From quince seed boiled in water, as the last. 1/4 oz. yields nearly 3/4 pint of strained decoction.
3. Pale gum arabic (picked), 1-1/2 oz.; rose water, 2 fl. oz.; pure water, 3 fl. oz.; dissolve.
4. Gum arabic, 3-1/4 oz.; water, 1/2 pint; dissolve, and drop in eau de Cologne, gradually, until the cloudiness at first occasioned ceases to be removed by agitation; the next day decant the clear portion. All of the above are very superior, and keep well.
5. (Redwood.) Gum tragacanth, 1-1/2 dr.; water, 7 oz.; proof spirit, 3 oz.; otto of roses, 10 drops; macerate 24 hours, and strain.
6. Malt, 7 oz.; hot water (that will barely permit the finger to be held in it without pain), 1/2 pint; infuse in a covered jug or basin, gently press out the liquid, and as soon as cold add of proof spirit (or brandy or Cologne water), 2-1/2 fl. oz. and strain.
_Obs._ Bandoline is used by ladies and by hairdressers for stiffening the hair, and to make it curl firmly and remain in place. It is applied either by moistening the fingers and passing the hair through them, or by means of a small sponge. See POMMADE.
=FIXED AIR.= See CARBONIC ACID.
=FIXED OILS.= See FAT and OILS.
=FLAKE WHITE.= See WHITE PIGMENTS.
=FLAME.= Gas or vapour in an incandescent state. The light emitted from pure flame is exceedingly feeble; illuminating power being almost entirely dependent upon the presence of solid matter. See ILLUMINATION, and _below_.
=Flame Colours.= The vapours of metallic compounds communicate colours to flames. The characteristic colours of some metals are very beautiful, and their exhibition forms a favorite experiment of chemical lecturers. The coloured flames are generally produced by the combustion of alcohol or rectified spirit upon certain salts in fine powder. In this way a GREEN colour is communicated by boracic acid or chloride of copper; a RED one by the nitrates of iron, lime, or strontia; a VIOLET, by potassa and its salts; and a YELLOW, by nitrate of soda. Messrs Church and Crookes have recently described a mode of exhibiting the characteristic flames of the metals which is admirably adapted for the lecture-table.[312] 'Gun-paper,' made in the same way as 'gun-cotton,' is to be soaked in solutions of the chlorates of the different metals, dried with care, and kept dry. A good 'gun-paper' for the purpose is prepared by soaking strips of Swedish filtering-paper for ten minutes in a mixture of 4 parts oil of vitriol with 5 parts strong nitric acid, both by measure. The strips, when taken out of the acid, should be washed first with cold, and then with hot rain or distilled water, till the washings are no longer sour to the taste. The solutions of the metallic salts need not be very strong; but if they are warm, the strips of 'gun-paper' will be more easily and completely saturated with them. Since some of the chlorates attract moisture from the air, it is better to dry the papers prepared with them before the fire previous to lighting them. They are shown to best advantage when a strip is loosely crumpled up into a pellet, lighted quickly at one corner, and thrown up into the air against a dark back ground. They leave after burning, if properly prepared, no ash whatever. Paper prepared with the salt of potassa gives a flash of VIOLET flame, that prepared with the soda salt the characteristic YELLOW flame, and that with chlorate of baryta a very beautiful GREEN light. The chlorates of strontium, lithium, and calcium, when thus ignited, give intense colours. The VIOLET-BLUE flame of copper is well seen, even with the chloride of that metal, while paper soaked in nitrate of potassa shows the potassium flame better than if the chlorate be used. 'Gun-paper' prepared with a very weak solution of chloride or chlorate of thallium shows the characteristic SPRIG-GREEN flame of that metal with great distinctness. Chlorate of barium, being an article of commerce, may be employed for the preparation of the other chlorates, it being merely necessary to add to this salt in solution an exactly equivalent quantity of the sulphate or carbonate of the metal whose chlorate is desired. For instance, in order to make 'chlorate of copper,' 15·1 gr. of chlorate of barium being dissolved in hot distilled water, a boiling solution containing 12·5 gr. of pure crystallised sulphate of copper is to be added to it. Insoluble white 'sulphate of baryta' falls, while the solution, filtered and evaporated, yields the new chlorate in crystals. See FIRES, PYROTECHNY, &c.
[Footnote 312: See 'Intellectual Observer,' April, 1863.]
=FLAN'NEL.= It has been shown by the experiments of Count Rumford that the conducting power of the different materials employed for clothing varies considerably. A thermometer surrounded with cotton wool, and heated by immersion in boiling water, took 1046 seconds to lose 135° Fahr., when plunged into a bath of melting ice; but, under the same circumstances, when sheep's wool was employed, 1118 seconds elapsed before a like sinking of the thermometer took place ('Phil. Trans.,' 1792); thus showing the greater conducting power of the former, and consequently the superiority of the latter substance for the manufacture of warm clothing. But the chief advantage of wool, as an article of underclothing, depends less upon its actual power of conducting heat than its peculiar texture. Flannel acts as a gentle stimulus on the skin, and exercises the most beneficial action, by keeping the pores clean, and in a state most favorable to perspiration. This action is a species of friction similar in character, although inferior in degree, to that of the common flesh-brush or horse-hair glove, so long employed as a skin stimulant. Flannel has also the advantage of absorbing the perspiration as soon as emitted, and allowing its watery portion to pass off into the atmosphere almost as soon as formed, but this is not the case with cotton and linen fabrics. The different effects of flannel and linen are particularly susceptible during brisk exercise. When the body is covered with the former, though perspiration be necessarily increased, the perspired matter freely passes off through the flannel, and the skin remains dry and warm. If the same exercise be taken in linen shirts, perspiration, as in the former case, is indeed also increased, but the perspired matter, instead of being dispersed into the atmosphere, remains upon the linen, and not only clogs the pores of the skin, but gives a disagreeable sensation. From this property of flannel, persons who wear it next the skin seldom catch cold from changes of temperature, even though perspiring profusely; but in similar cases, when linen or calico shirts are worn, chilliness immediately comes on, followed by sniffling, sneezing, and cough, and all the other symptoms of severe catarrh.