Salt spray

“ SALTPETRE The attention of the ancients was naturally attracted by the efflorescences which form on certain stones, on walls, and in caves and cellars; and the Hindus and nomad Arabs must have noticed the deflagration of at least one of them when a fire was lit on it. These efflorescences consist of various salts,—sulphate and carbonate of soda, chloride of sodium, saltpetre, &c.—but they are so similar in appearance and taste, the only two criteria known in primitive times,19 that early observers succeeded in discriminating only one of them, common salt, from the rest. ”

“ Fortunately, chemists have lately paid attention to the advantages of the use of pure salt in various industries, with the result that at least two chemically pure products are now available. The use of these salts should be general for the cure of hides and skins, as they are quite dry, and, therefore, easily spread. As a curing agent, they are much more effective and lasting than common salt. ”

“ The fire must be kept up all the time, night and day, if it goes out your salt will be spoiled. If you make a great quantity of salt, it is as well to have a tin especially made for the purpose, and it should be wide and shallow, a sort of tray about four inches in depth, supported on legs nearly a foot high. You can have a slow fire under this, or if stood in the sun the water will be evaporated and a layer of salt left. As the sun draws off the water you want to add a little, till you have as much salt as the tray will hold. ”

“ As you walk along on top of them, you can smell a faint violet perfume from the salt. Thatch is put over the cones to protect them from the rain, and there they stand till some of the impurities drain away. This salt is not perfectly white, [Pg 98] because the workmen cannot help scraping up a little of the gray or reddish clay with it. Most of it is sold as it is, nevertheless, for many people have an absurd notion that the darker it is the purer it is. For those who wish to buy white salt it is sent to a refinery to be washed with pure water, then boiled down and dried. ”

“ Salt-petre is separated from the brine which first affords it, or from the water with which it is washed out of nitrous earths, by the process commonly used in crystallizing salts. In this process the brine is gradually diminished, and at length reduced to a small quantity of an unctuous bitter saline liquor, affording no more salt-petre by evaporation; but, if urged with a brisk fire, drying up into a confused mass which attracts water strongly, and becomes fluid again when exposed to the open air. ”

“ Coarse salt scattered about wardrobes, closets, cupboards, etc., will keep moths and silver fish away. Any rooms where they are, should be swept with salt. It does not injure carpets, on the contrary it tends to brighten the colours, and is a great purifier removing stuffy and musty smells. ”

“ This test is done by dropping in some nitrate of silver solution, which produces a white precipitate, caused by the silver combining with the chlorine, which is the principal element in common salt. This is an excessively fine test, and the nitrate of silver will detect an incredibly small trace of common salt in water. The worst effect that common salt has in water, is to cause priming. Where it is present to any great extent, the blow-off cock should be used frequently on the road; and a surface-cock is quite an aid in keeping the boiler in order. ”

“ The three projections on the upper rim seem to have been intended for the support of a cover, perhaps a napkin, as it was considered desirable to keep the cover clear of the salt itself: "loke that youre salte seller lydde touche not the salte," saith the "boke of keruynge." It appears from numerous allusions to the fact, that the state salt was used by the "sovereign" or entertainer only; and it is not unlikely, from the great number of salts mentioned in old inventories, that when possible each guest also had one for his particular use. ”

“ The deposits, which are found at a considerable height above sea-level, are of great but undefined magnitude, as the lowest strata has been bored through for a thickness of 72 feet, without penetrating the formation. The rock salt here was acknowledged to be purer than any previously encountered in Cheshire, and the brine derived therefrom, containing 26·100 chloride sodium by weight, yields on evaporation an exceptionally high class of white salt. ”

“ The ‘mother-liquor’ of the ‘crystallisers’ is pumped back into the evaporating pans for further concentration. The crude blackish salt (hydrochlorate) thus obtained is contaminated with tarry and oleaginous matter, free acid, water, &c.; from part of which it is freed by exposing it in a layer about 4 inches deep, on a cast-iron plate gently heated by a zigzag flue of a small furnace, until all the water is expelled; care being taken that the heat never rises high enough to volatilise the salt. This operation is generally performed under a dome, or the expanded throat of a large chimney. ”

“ Usually, in 5 or 6 days the incrustation becomes so thick that it interferes very materially with the evaporation, causing a great loss of fuel, as gypsum is one of the poorest conductors of heat. The workman therefore draws the salt from the kettle, removes the remaining brine to within a few gallons, and refills the kettle with fresh water. After a continuous boiling of about half an hour, the greater part of the adhering salt has dissolved and the rest of the incrustation can easily be removed. ”

“ It is only volatile when there is more than a due proportion of either of the constituent parts. In these cases the smell of the salts is extremely pungent, but very different from one another; being manifestly acid, or alkaline, [Pg 171] according to the prevalence of each of these airs respectively.
Nitrous air admitted to alkaline air likewise occasioned a whitish cloud, and part of the air was absorbed; but it presently grew clear again; leaving only a little dimness on the sides of the vessel. This, however, might be a kind of salt, formed by the union of the two kinds of air. ”

“ Particles of chloride of sodium in volcanic ejections were no explanation of the formation of huge deposits of rock-salt, and since it was realized that salt in large quantity can only be obtained from salt water, and that it cannot be got naturally from the sea, it became evident that what man does in isolating tracts of sea-water to produce salt by solar evaporation, must have been practised by nature on an extensive scale in all ages. ”

“ While the curing of wet hides with salt or in brine is more satisfactory than drying them, the use of ordinary 71 salt is not an ideal method, as 10 per cent. brine dissolves hide substance. The recent introduction of a pure dry salt (99-98 per cent.) and of a sterilised salt for commercial purposes has to a large extent removed the objections to ordinary salt. Dry sulphate of soda is also a satisfactory cure. ”

“ While the largest size triple-effect vacuum plants are capable of turning out 1,000 tons of salt per diem, with brine at or near saturation, and produce about 6 tons of salt for the combustion of 1 ton of coal, it is a very expensive process to operate as well as to install. ”

“ These salts, or compounds, are mingled with sawdust, or some other porous substance not acted on by the gas, before being put into the purifiers; and after they become saturated with the vapour, the newly-formed hydrochlorate or sulphate (according to the salt or mixture employed) is washed out of the mass with water.
Besides the usual sources of SAL AMMONIAC (and the other ammonia-salts of commerce) it has been proposed to obtain it from guano, peat, shale, &c., as noticed under Sesquicarbonate of Ammonia (suprà) ”

“ Prolonged soaking in cold water dissolves a serious amount of hide substance. Soaking in brine may be advantageous, as it prevents putrefaction to some extent. Caustic soda, sodium sulphide and sulphurous acid may also be advantageously employed on account of their softening and antiseptic action. In treating salted goods, the first wash water should always be rapidly changed, because, as mentioned, strong salt solutions dissolve hide ”

“ In each gallon of river or rain water dissolve about six ounces of sea-salt, either by stirring it or suspending it in the water in a linen or muslin bag. It dissolves as readily in cold as in hot water. Sea-salt is produced by evaporation of sea-water. Common salt is sometimes supplied in place of it; but the genuine sea-salt, manufactured by well-known firms, which can be procured of any grocer or of most chemists, is specially prepared to enable persons to have a salt-water bath at home. ”

“ Is it not a blessing to know that nature has munificently provided a means whereby these distressing evils may be checked and definitely eradicated by a daily use of such an enemy to, and destroyer of, disease as the chloride of sodium, universally known as common salt? ”

“ The kind of salt generally used in large plants for this purpose is a rock salt, which is a mined product run through crushers and screens. Large lumps are more or less objectionable and if allowed to be used will injure the appearance of the hide. Hides in a pack weigh very heavily per cubic foot and the lower hides are subject to a considerable pressure, or weight. Large lumps of salt between the hides in the pack make bad looking indentations, although they do not necessarily injure the hides for tanning purposes. ”

“ In all Salts, that a most potent Fire doth lurk as being laid up therein, those have best known who have the labours of the fire thoroughly viewed and certainly known. For through the efficacy and operation hereof, salts are reduced unto a fiery force, or power, or unto a moist fire, out of which they before arose, after the laying down of their earthliness, yet one salt draws out one fire far unlike to the fire of another, so that this is volatile, the other is fixed, and remaining constant in the fire ”

“ The large grained, flaky salt was made with an evaporation conducted at the heat of 130 or 140 degrees, and the pan was filled once in every forty-eight hours; while in the case of fishery salt, the brine was brought to a heat of from 100 to 110 degrees of Fahrenheit, and five or six days were required to evaporate the water of solution. In the course of these several processes, various additions were often made to the brine, with the view of promoting the separation of any earthy mixture, or the more ready crystallization of the salt. ”

“ Now, owing to chlorine gas, the process is completed in a few hours, and a comparatively small building is quite sufficient for the purpose; the fibre is beautifully and permanently whitened, and the manufacturer experiences the pleasing satisfaction of a more rapid remuneration.
Where would be our delicately white textile fibres were it not for the abundant and inexhaustible supply of salt? How should we be enabled to cause vegetable colours to vanish as if touched by the hand of a magician were it not for the bleaching properties of chlorine? ”

“ By multiple effect evaporation, a great economy in the amount of steam required is effected. Between the evaporation of brine and that of other liquors, the chief difference to be noted is that in the multiple effect system, each pan or unit is supplied with its brine independently of the others, and graining goes on in the pans, whereas in concentrating other liquors the pans are fed from the first to the second and from the second to the third. The removal of the salt from each pan has, therefore, to be arranged for. ”

“ Let it be clearly understood that all commercial salt is produced either from the sea or from rock-salt. Sea-water is evaporated to precipitate its salt either by the heat of the sun or by artificial heat. Rock-salt is mined and refined for market purposes, and it is resolved into brine from which the salt is extracted by solar heat or the process of boiling, but whether the salines are obtained from salt lakes or from natural brine springs, or are prepared by flooding salt deposits with water and pumping it out in the form of fully saturated brine, rock-salt is the foundation for them all. ”

“ The brine is run through long, shallow tanks and the heat is applied through steam pipes inside of the pan. The salt settles to the bottom of the pan and large rakes operated either by hand or machinery collect the salt.
In the Vacuum Pan process tiny cubes of salt are formed and settle to the bottom of the pan in which a vacuum has been created. The salt is then drained out and is ready for drying.
Variations of the two above processes make possible the production of certain grades of table salt. Oftentimes the brine is relieved of impurities through the action of certain chemicals. ”

“ The greatest quantities of this salt are to be found in those earths which have been drenched with urine, or other animal excrements. Now as the rubbish of old houses in great cities is in this class, it comes to pass that when the Salt-petre workers evaporate a nitrous lixivium drawn from that rubbish, as soon as the evaporation is brought to a certain pitch, a great many little crystals of sea-salt form in the liquor, and fall to the bottom of the vessel. ”

“ We may assume, as matter of argument, that if the 'Lixator' functions best on rock salt of average sodium chloride content of 98.2%, the lessee might be required to use only salt meeting such a specification of quality. But it is not pleaded, nor is it argued, that the machine is allergic to salt of equal quality produced by any one except International. If others cannot produce salt equal to reasonable specifications for machine use, it is one thing; but it is admitted that, at times, at least, competitors do offer such a product. ”