It must by this time have become evident to scientific investigators and practical salt-men that the solution of the problems of economical manufacture and increased output lay in the application and regulation of heat. Christopher Chrysel, of Leipsic, after fourteen years of “great industry, much pains, and cost” spent in the practice and study of salt-making in Cheshire, published the result of his labours in 1787. Chrysel claimed that by his method “with the least Fire and Coal the most Salt can be made and the greatest Profit received such as in no other way can possibly happen,” but curiously enough the improvement for which he obtained a Royal Patent, was primarily based upon a more advantageous arrangement of the brine pans, while the improvement effected in the furnace was treated as a matter of only subsidiary importance. Chrysel demonstrated his method at Bye Flat, near Northwich, in Cheshire, in June, 1776. The experiment was carried out in the presence of witnesses, the same pan was used in testing both the old and the new methods, the same two salt-boilers were employed in conducting both operations, and the amounts of fuel consumed and salt produced were carefully weighed and attested. The results were recorded in the following report furnished by the Liverpool Agent of Mr. Richard Kent’s salt-works at Bye Flat—
A SALT STORE-SHED
“In three ‘firings’ of 2 Furnaces under a salt pan set up on the old plan ten years ago and constantly worked till the present time—24 feet long: 15 feet broad and 12 inches deep—filled with Brine three times in a half week, and boiled down each time in 24 hours and the salt drawn out there was burnt 5½ tons of Coal and made 7 tons 31 bushels, or 155½ cwts. of salt.
“After the experiment the Patentee, Mr. Christopher Chrysel, set up the same pan on his improved Patent Method, and then in three similar firings in half a week as before there was only burnt 3 tons 5 cwt. of coal and made 8 tons 2 cwts. or 162 cwts. of salt=2 tons 10 cwts. of salt per ton of fuel.”
Chrysel says in his treatise that the pan mentioned in his experiments—24 ft. long, 15 ft. broad, and 12 in. deep—will be regarded by his German readers as of phenomenal bigness, but he explains that in England it is looked upon as only a medium-sized receptacle. The pans in use in Cheshire at this period were of various sizes, but the tendency was to introduce pans of increasing dimensions. “Indeed I can with all truth say,” he writes, “that in England I have seen with my own eyes, pans two, three and four times as big (as the one he used at Bye Flat) and have measured them with my own hands, and have proved each one designedly and have seen and marked and become persuaded that from large salt pans the greater advantage and the most noted cheapness in the manufacture of salt depend and proceed.”
In the course of his experiments with pans of all sizes, he proved that in a small pan, 8 ft. square and 9 in. deep, heated with one furnace, he obtained in five weeks a clear profit of £35 15s. 2d., while in one pan, compounded out of five of the small pans, and heated with two furnaces, the profit of one week’s working was £42 15s. 5d., or a net additional profit of £7 0s. 3d., and the saving of four weeks in time and labour.
He further experimented with three of the largest pans for one week, with the following results—
“The first—36 by 25 feet and 13 inches deep holding 975 cubic feet of Brine—burnt in 3 Furnaces in one week 12 tons of coal and made 32 tons 2 cwts. of salt.
“The second—40 by 27 ft. and 13 inches deep holding 1170 cubic feet of brine—burnt in 3 Furnaces in a week 15 tons 18 cwts. of coal and made 34½ tons of salt.