July ist, 18S7.] 



SCIENTIFIC NEWS. 



ride, are allowed to drain away, they being fortunately 

 more deliquescent. The flow of water is often assisted by 

 pumping ; and when a finer description of salt is required 

 a further process of washing in fresh water and re-evapo- 

 ration is gone through. 



Bituminous deposits are often found in connection with 

 salt, and, indeed, there seems some mysterious affinity 

 between the two which has never been satisfactorily ac- 

 counted for. Petroleum and brine seem to go hand in hand, 

 and in China there are some brine springs in which the 

 natural gas that accompanies them is used to supply heat 

 for the evaporation. 



There are many rock salt districts in Europe. The Tran- 

 sylvanian and Wallachian mines are very important, but the 

 Wieliczka mine, in Galicia, is the best known, and has often 

 been described. The bed of salt is said to be 500 miles 

 long, twenty miles broad, and 1,200 feet thick. The length 

 of chambers and galleries amount to thirty miles, and fiftj'- 

 five thousand tons of salt are taken out yearly. As to other 

 countries, the United States appear to be ill provided with 

 salt, and British India is also lacking in this great essential 

 to human existence. South America has brine springs, but 

 does not work them. China and Siberia are well supplied, 

 whilst Persia is said to be more richly endowed with salt 

 than any other country in the world. 



Having disposed of these general particulars relating to 

 foreign salt, we will now proceed to deal with the district 

 more particularly the subject of this notice. 



The town of Northwich is the chief centre of the great 

 salt-producing district of Cheshire. It has very much the 

 general aspect of any other old-fashioned country town. 

 Perhaps the first comment a stranger would make would be 

 that the builders of the district must be of a particularly 

 "jerry" order, and construct theirhouses without any founda- 

 tion to speak of. Such a conclusion would be justifiable at 

 first glance, but would be nevertheless a wrong to the builders 

 of Northwich, for they must put in exceptionally sound 

 work, otherwise their constructions would not stand brick 

 on brick at all, as will be acknowledged by those who have 

 the patience to read to the end. 



Northwich, physically and economically, is founded on 

 salt. Its inhabitants live, thrive, and have their being on 

 salt. The river Weaver which flows through the town 

 runs above salt, and carries little else but salt on its ex- 

 cellently preserved channel. All round the district there 

 are engines at work, pumping up salt in the form of 

 brine from beneath the thin crust, that it would be 

 ridiculous to describe as the solid earth. When a North- 

 wich householder finds his dwelling gradually settling into 

 the nether depths he does not complain over much, know- 

 ing it is the common source of all his and his fellow- 

 townsmen's prosperity that is lowering him a yard or two 

 below his normal level. 



There is little to describe in the manufacture of ordinary 

 domestic salt, which is obtained from the brine ; the rock- 

 salt quarried from the mines in the manner to be presently 

 described being used mostly for manufacturing purposes. 

 Beneath the county of Cheshire there are vast deposits of 

 the edible mineral ; how vast no one knows, but they are 

 to all appearance inexhaustible. A stream of water will 

 break into one of these deposits, and if left alone would rise 

 to the surface in the shape of a heavily-charged brine 

 spring, or perchance find its way below to a river, or to the 

 common source of all salt — the ocean. Such springs are, 

 however, too valuable to be allowed to waste their riches 

 in this way, or wander off to other districts, so bore-holes 

 are sunk in all directions in order to intercept and bring 

 them to the surface. When a successful prospector " strikes 

 salt" he erects a pumping engine and draws up the brine. 



The liquor is run into large iron tanks, and by fires made 

 under these the water is evaporated, leaving the salt to be 

 drawn off, dried, and packed. Such is the mode of work- 

 ing in the present day, just as it was in this same district 

 in the dajs of the Roman occupation of these Isles, ex- 

 cepting that the Romans had no steam-engines to bring the 

 brine to the surface. The pans, however, want tending 

 during the operation, otherwise the salt would settle and 

 cause them to be burnt, because the water would not come 

 in contact with their sides and bottom, and so carry off the 

 heat. A given quantity of water will only hold a certain 

 amount of salt in solution, and as soon as that amount is 

 exceeded by reason of the evaporation, the salt forms in 

 thin flakes on the surface, and has promptly to be drawn 

 to the sides by men with long-handled rakes, otherwise it 

 would sink to the bottom, and, as we have said, cause the 

 pans to burn. The evaporating sheds of a salt works are 

 a picturesque sight. The muscular figures of the operatives 

 — and a man must have muscle for the heavy work at the 

 evaporating pans, with but little clothing on — appearing and 

 disappearing amongst the ascending clouds of vapour, and 

 whisking off the flakes of salt with their long-handled im- 

 plements, aft'ord an effective picture, such as one seldom 

 sees in any industry in these prosaic days of mechanism. 

 When the wet salt is taken from the pans it is put into 

 moulds and taken to stoves to be dried, and then we have 

 salt fit for use. 



All salt, however, is not used for domestic purposes, 

 large quantities being employed in various processes of 

 chemical manufacture. A good deal of this is got from salt 

 mines, the " rock salt" thus produced being quarried below 

 the surface, and brought up a shaft, much in the same 

 way that other minerals are. At Marston, near Northwich, 

 there is such a mine, which we lately had, through the 

 kindness of the proprietors, an opportunity of visiting. 

 The shaft of the Marston mine is no yards deep. The 

 visitor stows himself away in the bottom of a capacious 

 bucket, perhaps with one or two fellow-explorers, and an 

 attendant stations himself straddlevvise across the iron bow 

 to which the chain is attached, in order to see that all goes 

 right. Soon the winding engine begins to uncoil the length 

 of wire rope, and the bucket falls rapidly through the three 

 foot and a half diameter iron tube, which forms the lining of 

 the shaft. At ordinary times the depths of a salt mine are of a 

 stj'gian blackness, except where the candle of the miner may 

 perhaps be tracing a zig-zag thread of light as he picks his 

 way over the boulders of salt in the distance. So we found the 

 Marston mine on our first arrival below ; but the hospitable 

 proprietors occasionally organize a grand illumination, and 

 we had the good fortune to witness one of these displaj's. 

 Under these conditions, a salt mine, generally so gloomy 

 and dark, becomes a most charming spectacle. Points of 

 light, arranged in symmetrical lines and curves, trace out 

 the contour of the vast chambers and galleries, the walls of 

 which are composed of the beautiful crystals of rock salt. 



The main division of the mine is about eleven acres in 

 extent, and twenty-six feet in height. The roof of this vast 

 underground chamber is supported by massive columns, ten 

 yards square, where the salt has been left for the purpose. 

 These are placed twenty-three yards apart, and all between 

 the rock salt has been hewn away. One hundred yards 

 above on the surface of the earth runs a river and a rail- 

 way, whilst the road of the district crosses, but no sound of 

 the world above reaches through the solid crust of earth 

 which forms the roof of the mine. 



Within recent times compressed-air machines have been 

 introduced for cutting the salt. On the surface above there 

 is a powerful engine which compresses the air to a pressure 

 of 70 lbs. to the square inch, and this compressed air is 



