The Graphic Excitement of Mocha and Related Dipped Wares – The Journal of Antiques and Collectibles – May 2006
By Jonathan Rickard
The following is an excerpt—Chapter 5, The Multichambered Slip Pot—from [amazon_link id=”1584655135″ target=”_blank” container=”” container_class=”” ]Mocha and Related Dipped Wares[/amazon_link], 1770-1939, by Jonathan Rickard, published in 2006 by the University Press of New England. Additional images have been supplied to The Journal of Antiques and Collectibles by the author. Reprinted with minor modifications with permission.
The earliest use of slip—fluid clay—to decorate fine creamware and pearlware happened around 1770 with marbled surfaces that imitated natural geological surfaces. At about the same time, potters in Staffordshire began to create geometrically precise patterns on mugs, jugs and bowls by using a machine adapted from the metalworking industry, the engine-turning lathe. By the early 1790s, slip surfaces were being further decorated with an acidic colored solution using stale urine, vinegar, turpentine, or a tobacco infusion to create dendritic (tree-like) patterns called mocha after mocha stone, a type of chalcedony imported by British jewelers from Arabia through the port of Mocha (al Mukha), hence the name.Sometime around 1810, a device containing several slip colors began to be used in potteries to apply other types of decoration. With this tool, the turner added cable (earthworm), cat’s eyes, and twigs to his array of decorative devices.
It is not known when the multichambered slip pot first began to be used in pottery decoration but numerous clues suggest around 1810. The patent issued to Richard Waters of Lambeth in London in 1811 might be construed to be the starting point, but there are strong arguments against his being the innovator. (see sidebar) Nevertheless, it’s unlikely that such decoration was used much earlier. The shape of bowls is the first clue. It is generally conceded that the London shape was introduced in porcelain in 1807. It appears that by 1810, that shape dominated earthenware production to the exclusion of the previous Chinese-derived hemispherical shape.
Most often, the device used in production was divided into three equally-sized compartments to create what the potters called “cable” or “common cable”. In time the term fell into disuse and collectors began to refer to the serpentine ornaments as “earthworm”. Other decoration produced by the three-chambered slip pot included cat’s eyes and twigs, both terms established by collectors. These motifs virtually never appear on the early hemispherically-shaped bowls. Such rounded bowls reappear later but are thicker-bodied with turned, rounded bases. And there are rare exceptions. Evidence from the William Greatbatch archaeological excavation is that Greatbatch produced hemispherical bowls with rounded feet in the 1775-1782 period. A slip-marbled example of that period with blue-painted underglaze Chinoiserie ornamentation is in the collection of Colonial Williamsburg.
A book published in 1839 dealt with manufacturing processes of all kinds of industries and described in complicated fashion the procedures involving the multi-chambered slip pot on pottery: “Ornaments and Colouring. – Common stoneware is coloured by means of two kinds of apparatus; the one called the blowing-pot, the other the worming-pot.” Andrew Ure’s description of the worming pot, though he changes the terminology, follows: “The serpentine or snake pots, established on the same principle, are made of tin plate in three compartments, each containing a different colour. These open at the top of the vessel in a common orifice, terminated by small quill tubes. On inclining the vessel, the three colours flow out at once in the same proportion at the one orifice and are let fall upon the piece while it is being slowly turned upon the lathe; whereby curious serpent-like ornaments may be readily obtained. The clay liquor ought to be in keeping with the stoneware paste.” If Ure had been more deeply involved in the pottery industry, he would have used the word slip rather than clay liquor and would have probably known that the serpentine ornaments he described were called cable by the potters. Nevertheless, it’s a description written when the practices were very much in use. The final sentence indicates that slip, to fit well onto a clay body, should contain essentially the same ingredients as the body (i.e. ball clay, flint, flux, etc.).
Another 19th-century published work, Muspratt’s Chemistry, described the process this way: “When a marbled appearance is required, the tinted mixtures are placed in separate compartments of one vessel furnished with a spout in connection with the several chambers. On their exit from the vessel, all the colors flow out in a single stream, but unmixed with each other. This stream flowing upon the ware causes a waved or variegated appearance according to the regularity of the motion given to the piece, and articles so decorated, are commonly called depped and mocha ware.” Obviously, depped refers to dipped, but the use of the term mocha to describe variegated and cable decoration in 1860 gave rise to the expanded use of the term, broadening its usage from dendritic decoration to include multi-colored slip patterns.
A large three-chambered earthenware slip pot is in the Potteries Museum in Stoke-on- Trent, dated 1833 and inscribed William Shaw. Unfortunately, the directories for Stokeon- Trent for the nearest years (Pigot’s Directory of Staffordshire for 1830 and for 1834) list only the manufacturers, including Kitty Shaw, China manufacturer of Market Place, Lane End (moving before 1834 to Chancery Lane) and John Shaw, earthenware manufacturer, of Green Dock, Lane End. Don Carpentier constructed a similarly-sized example based on the Shaw model and indicated that, fitted with goose quills, it worked very well. It had been thought that the size was much too large, but Carpentier’s opinion is that, in a production setting, the size was appropriate to the needs of the turner. If it had been smaller, it would have been necessary to stop the flow of production too frequently to re-fill the device, losing not only time, but the rhythm necessary to produce the smoothly-flowing slip designs. It appears, from Carpentier’s experience, that a stream of continuous work is necessary to produce the kind of smooth, flowing, rhythmic undulations that the worming, at its most attractive appearance, exhibits. Don also constructed several tinplate examples and uses them regularly in production.
A different color of slip was placed in each of the three compartments. Goose quills were inserted into the holes in the narrow end. The quills were gathered together at the very end and packed round with soft clay to hold their position. To the very tips of the quills, a small metal device could be attached to constrict the flow to varying degrees, based on the size of the aperture. With the slip at the correct viscosity, when the device was tipped forward a single drop of slip in the three colors appeared. When the drop fell onto a pot on the lathe, it formed the decorative device collectors have dubbed cat’s eye. On some examples, it appears that only two colors were used. Here it is likely that one of the three colors had been consumed in production and, owing to the speed of the worker trying to produce the greatest number of vessels in the shortest time, work continued. An alternate explanation would be that the liquid content of that particular color had dried to the point that the slip could no longer flow through the hollow tube.
If the turner allowed a steady series of drops to fall overlapping each previous drip, the result was common cable, better known to collectors as earthworm. Cable also varies considerably from pot to pot, not only in the pattern created by the turner – some merely rise and fall as the turner moved the slip cup from left to right over the slowly revolving pot on the lathe – others form intricate loops. Here, too, the level of fluidity in the three slips as well as the relative dryness of the body played a strong part in the success of the final appearance. Some patterns are so involved that it appears that the turner was showing off. It is known that one Glasgow-based pottery produced wares decorated with a four-chambered slip cup. Canadian archaeologists have numerous sherds found in fourcolored slip decoration bearing the mark of John Thomson & Co. At the request of Parks Canada, Don Carpentier has recreated a number of examples using the sherds as a guide to patterns and colors.
A third type of decoration was created by the turner with the multi-chambered slip cup: touching the quills to the pot and, with the slip flowing, the turner twisted his wrist while quickly dragging the tips of the quills to create a series of back-and-forth curls connected to each other in a branching way referred to by collectors as twig. Here, too, two- and four-colored examples can be found. And, as with most other slip decoration techniques, appearances can vary greatly owing to the skill of the turner and by combining twig with other motifs.
Where the variegated patterns and mocha were reminiscent of geological surfaces, engine-turning and three-chambered slip decorations were not. Here is where the concept of fancy takes hold and allows the turner to enter the realm of the abstract. There are numerous but rarely encountered variations of decoration produced with the three-chambered slip pot. Sherds from the Firth of Forth potteries outside Edinburgh as well as from the Enoch Wood waste pit in Burslem include vessels with trailed wavy bands of three colors similar to common cable but smoother. Occasionally cat’s eyes and cable designs are found which have been combed, usually horizontally. Two jugs are known with three-colored devices that resemble comet tails and sometimes items have dragged cat’s eyes. Some of these represent intentional variations while others are the result of conditions that thwarted the intent of the turner.
Richard Waters Patent In June of 1811, a Mr. Richard Waters, potter of Lambeth, London, was granted a patent for “making or clouding the ‘Welsh ware’, by using a number of pipes instead of one in distributing the colour”. The pertinent passages of this patent read as follows: “To all to whom these presents shall come I, Richard Waters of Shore Street Lambeth in the County of Surrey Potter send greeting…. “Thirdly I do mark or cloud the ware called Welsh ware by using a number of pipes or tubes at once instead of one pipe or tube through which the coloring slip or material is made to flow by which means the operation is better and more speedily performed. Fourthly I do make of earthen ware the jambs [?] or pieces for chimnies and silos [?] for pouring or faring Houses or for paving and Hearths for fire places and Ballustrades for large Bridges Balconies and the like and also Bricks or pieces for building all severally veined coloured or variegated either by the last mentioned process for Welsh ware or by putting together masses of clay differing from each other in the composition and nature and in the admixture of stony or metallic or other mineral substances so as to differ in their colors and appearance when baked and kneading or working up the said masses so put together until the whole mass shall be moderately but not too intimately or minutely clouded And I do declare (as an instruction for this last mentioned process of kneading or working that if the said whole mass be not sufficiently kneaded or worked then the colours after baking will appear in coarse lines veins or patches And also that if the kneading or working be continued too long the several colours will either be seen in minute and indistinct marks or will be confused together but that the proper degree of working may known by baking a small proof or trial piece by the appearance of which and from his knowledge of the qualities and quantities of the several kinds of clay made use of at any time the Manufacturer will be enabled without difficulty to produce that variegated body which shall or may be most acceptable to the taste of his employers…”
Only the segment following Thirdly was quoted by Llewellyn Jewitt, leading to the supposition that this was the so-called three-chambered slip pot or worming pot. In the context of the entire patent, it appears that Mr. Waters was involved in the manufacture of architectural ceramics (as one might suspect by his address) and possibly house-shaped pastille burners or farings. It is possible, though not likely, that this describes the process of decoration creating techniques known today by collectors as earthworm, cat’s eyes and twigs. More likely it describes his method of using slip to create a variegated appearance, an alternate to his more carefully described method using different colored clays, the process we call agate. This makes sense. Just as with wooden furniture, interior ceramic architectural features were sometimes decorated to mimic the appearance of marble. Both slip-marbling and the process of wedging different-colored clays together to create the appearance of agate were in use in the mid-to-late eighteenth century. Josiah Wedgwood himself had written of a process used to decorate tile flooring using a three-chambered slip cup as early as 1769. Nowhere in his lengthy description did he make any mention of similarly decorating pots. Apparently no one had previously patented the process. Despite his patent, Mr. Waters failed to become an important figure in British ceramic history.