distance of 130 feet from the commencement of the gypsum in the marl, we come to the strong brine, which rushes up to the surface as soon as it is bored into. This brine is ten feet deep, and the rock-salt is under this river of brine; but rock-salt has never been worked at Droitwich, as it is at Namptwich, in Cheshire. The salt is entirely obtained by evaporation of the brine. The depth of this brine has greatly increased within the past twenty years, and varies in different pits. Rock-salt has been repeatedly brought up by the boring rods when passed through the brine at Droitwich.

Dry rock-salt has been worked in only one situation in this county. It was discovered by Messrs. Fardon and Gossage, at Stoke Prior, in the year 1828; and the working of this has afforded an opportunity of our becoming better acquainted with the salt formation.

Before entering into the particulars of this salt mine, I must state the circumstances which led to the detection of the rocksalt at this spot. It is not here, as at Droitwich, that the brine springs to the surface. There is no salt at this place discoverable in the water of the ordinary wells, so that no indication of the presence of salt arises from them; but when the Worcester and Birmingham canal was cut, it evidently became a good speculation to discover brine, so as to have a salt manufacture there. A brine-smeller was therefore sent for from Cheshire, and after examining the country, he pronounced that there was salt to be found at Stoke Prior. Stoke Prior is three miles and a half north-east of Droitwich, and 160 feet higher than the bed of the Salwarp, where it passes through that town. We arrive at this place from Droitwich by the Bromsgrove road, and it is rather an uneven ride from the undulations of the ground. As immediately around Droitwich, so about Stoke Prior, there are rising hills of red marl, as at Hanbury, the church of which parish is ninety feet higher than Stoke Prior. There are also sections of marl near the Bromsgrove turnpike, resembling those before described. As to the rule by which the said Cheshire brine-smeller determined that there was salt at Stoke Prior I know nothing; but he attached great importance to what he called brine-slips. By brine-slips it appears that he meant a sudden slipping of the red marl, which sometimes occurs about Droitwich. It not very uncommonly happens in this district, that, on a sudden, a chasm will be formed, twenty or thirty feet long and a foot wide, by the giving way of the ground. These chasms are of great depth, and it is supposed by many persons that they communicate with salt strata below. Whether this be true or not, it is certain that the Cheshire salter assured his Worcestershire friends that he smelt the salt at these chasms, and hence inferred that the work of mining might be attempted with security. He probably drew his inference, not from the sense of smell, but from the appearance of the marl.

The result has at any rate proved him right in his prognostication; for solid rock-salt was here for the first time found in Worcestershire.

Section of the Strata at Stoke Prior.

Feet. Inches.

No. 1.-111 0 Red marl varying greatly in hardness, but not divided into strata. It abounds with water. A pit six feet diameter required a ten-inch pump working almost constantly to draw it. The water contains sulphate of lime, but no salt.

No. 2.-195 0 Red and green marl not stratified. This bed contains numerous perpendicular veins of

gypsum. It is perfectly free from water.

No. 3.- 24 0 Red marl, containing rock-salt nearly pure. This bed is exactly like the lower part of the preceding, except that rock-salt occupies the place of gypsum.

No. 4.- 06 First bed of rock-salt very impure; reddened by marl.

No. 5.- 3 6

No. 6.- 10 0

Red marl, with veins of salt.

Rock-salt, containing 25 per cent. of marl, (nearly red).

Green marl.

Red marl, with veins of salt.

Rock-salt, similar to No. 6.

Red marl, with veins of salt (reddened.) Thick bed of rock-salt, varying in the proportion of marl, containing from 20 to 7 per cent. (reddish.)

Red marl, with veins of salt (veins of suit flesh colour.)

Rock-salt same as No. 11-pierced 30 feet, and not passed through.

40 0

130 0

8 to 10 0

180 0

Section at Droitwich.

Red marl, free from gypsum, abounding with

water.

Red marl, with perpendicular veins of gypsum.
S Brine.

{

Rock-salt.

It may be observed that the beds of rock-salt are of immense thickness, and in this particular they bear a striking resemblance to those of Cheshire; they also resemble those in the varying degree of purity in which the mineral salt is met with. Some of these beds contain as much as twentyfive per cent. of marl, intermixed in small masses with the pure salt, whilst the proportion in other beds does not exceed seven or eight per cent. The veins of salt occurring in the beds Nos. 3 and 5, afford beautiful specimens of this mineral, the very small quantity of marl contained, being only sufficient to communicate a slight tinge of red, which rather adds to the beauty of their appearance. The proprietors of this rock-salt mine continued to excavate the solid mineral for a considerable period, and then, endeavouring to copy the operations of nature, they introduced a supply of fresh water, and converted their mine into an artificial brine spring. The dissolution of the mineral in water, was at first effected in large reservoirs after it had been drawn from the pit; but after the introduction of water, they were enabled to obtain a supply of brine by means of pumping, instead of having recourse to the much more expensive operation of excavating the solid beds of salt. After continuing this method of working for some months, a communication took place between the natural brine spring and the mine, which rendered the further introduction of water unnecessary.

It is most probable that all natural brine springs are produced by fresh water coming in contact with beds of rock-salt, and in this way becoming charged with saline matter. This notion is strengthened by the facts observed during the operations of sinking a salt pit. In Cheshire, where these pits have been excavated most extensively, it is quite uncertain, at commencing, whether the product obtained will be dry rock-salt or native bine; but it has been observed that where the latter is met with, it invariably occurs just before arriving at the rock-salt, and immediately on the surface of the first bed of this mineral. It has also been remarked in the operation of boring which is generally employed to ascertain the presence or absence of brine, that when this is present, the boring rods having arrived at a sufficient depth, fall some distance without encountering any resisting solid, and immediately the supply of brine springs up. The boring being continued, indications of rock-salt are next found. On the other hand where no fluid is met with, this non-resistance of the boring rods does not take place, thus shewing that the cavities where the brine springs occur are never in a dry state, and no doubt are produced by solution of the mineral, occasioned by its contact with water. At Droitwich the extent through which the boring rods have been observed to fall, has been increased, within the last twenty years, from about three feet to nine feet and upwards; from which we may conclude that a gradual wasting of the rock-salt continually takes place.

Where native brine is obtained, the supply of it is generally in great abundance. The Droitwich springs are so powerful as to raise the brine to the surface, and it overflows when not reduced by pumping. At Stoke Prior the supply is also abundant, but the level of the surface being much higher, the brine does not reach nearer to this than twenty yards. The brine at Droitwich is met with at the depth of 170 feet, while at Stoke Prior the depth is 330 feet. It is a remarkable fact that the difference in the surface levels of the two situations is just about equal to the difference of depths; shewing, that although the two places are nearly four miles distant from each other, the first bed of rock-salt is perhaps exactly at the same level.

Native brine, as it springs up from the earth, is beautifully transparent. Being derived from so great a depth it is not subject to those variations of heat which affect more shallow springs, the temperature observed being generally 52 degrees. The specific gravity at the Droitwich spring varies from 1.190 to 1.200 that furnished by the spring at the works of Mr. A. Reid, at Stoke Prior, has a gravity of 1.150; and the brine obtained from the spring of Messrs. Fardon and Gossage, at the latter place, possesses a specific gravity of 1.207, being fully saturated with salt. Perfectly saturated brine contains 26 per cent. of pure salt, and about a quarter per cent. of sulphate of lime. An imperial gallon weighs 12.07 pounds avoirdupois and contains 3.13 pounds of salt. The brine springs of Cheshire range in specific gravity from 1.150 to 1.200, and in their contents of salt from 20 to 26 per cent. Sea water contains rather more than two per cent. of common salt. Iodine and bromine have been discovered to exist in the salt springs of Cheshire, and in many other natural springs by Dr. Daubeny, but I have not been able to discover either of these powerful agents in the Worcestershire brine. In order to confirm or refute my own observations, I sent a portion of brine to my friend, Dr. Thomson, of Stratford, whose abilities as an accomplished chemist are well known, and he informs me that his analysis failed to detect either iodine or bromine in the brine. In procuring the salt from brine, the temperature required for boiling the solution is equal to 229 degrees of Fahrenheit's thermometer. This process yields what is usually called fine salt, the same that is employed for domestic purposes. Another kind, called broad salt, is made by evaporation at a lower temperature, by which the crystals being formed more slowly, and in a fluid not agitated by boiling, become more perfect in their form and of a greater size. This kind of salt is chiefly exported, and employed for curing provisions. When the process of evaporation is conducted still more slowly, very large crystals are obtained, which are sold under the name of British bay salt. During the making of fine July, 1835.-VOL. II. NO. XII. 3 c

salt, a considerable proportion of the salt attaches itself to the pan, and by the influence of the heat it becomes hard and adheres very closely to the iron plates. This accumulates to such a thickness as to render it necessary to be removed once a week, which is effected by allowing the fires to burn out, and then beating the cake with large hammers. The scale thus breaks up into pieces, varying in size from a foot square and two inches thick, to smaller dimensions. This product is called pan scale or picking, and when broken down to a coarse powder is found to be exceedingly useful as a dressing for light sandy soils. The large masses of pan scale are particularly suited to be laid down in grazing fields for the use of cattle, and its employment is strongly recommended to graziers, as the most beneficial results have been obtained from its use.

The pans employed in these operations are made of wrought iron plates, joined together by rivetting, and they vary considerably in dimensions. Those now in use for making fine salt are usually about 20 feet long by 20 feet wide and one foot deep. A pan of this size yields about 20 tons of salt per week. The pan is fixed in a building suitably arranged for the escape of vapour, and immediately contiguous to this is situated the drying stoves. The fire employed for evaporation is so placed that the smoke flues are passed through the drying stove before arriving at the chimney, and in this way sufficient heat is obtained for the drying process. As the evaporation goes on slowly in making broad salt, more extensive vessels are required to yield a sufficient quantity; some of them are upwards of 100 feet long. These pans at Droitwich are heated by fires, but at Stoke Prior the heat is applied through the medium of steam. The brine in this process is generally kept at a temperature between 160 and 170 degrees. The broad salt does not require to be dried in a stove; it is therefore thrown loose into a warehouse ready for exportation.

The labour of making salt is usually paid for by contract, at the rate of two shillings or two shillings and sixpence per ton weight. A considerable part of this labour is performed by females, who are said to withstand better the influence of heat in the drying stoves, where much exertion is used in moving the blocks of salt into various situations to promote and complete their perfect drying. The temperature of the stoves ranges from 120 to 130 degrees. The remuneration obtained by the work-people varies from fifteen to twenty-five shillings per week, according to the situation they occupy, either as contractors for the working of a pan, or labourers employed under the contractors.

Previous to the year 1823, a duty of £30 per ton weight was charged by the government on all manufactured salt. In this year the rate of duty was decreased to £4 per ton, and in 1825 it was entirely taken off. The beneficial effect of liberating a