Chats on Old Earthenware

by Arthur Hayden

It is, therefore, refreshing to find, as one does undoubtedly find in Staffordshire salt-glazed ware, one of the most remarkable and original outbursts in English art pottery that has taken place. This delicate stoneware is as thin as some of the Oriental porcelain, and possesses a grace and symmetry peculiarly its own. In some of its decorations it bears a likeness to Chinese work. This does not detract from its high place as a ceramic record. On the contrary, this similitude is a tribute to pay to its artistic excellence, for there is very little earthenware that came out of Staffordshire that will bear comparison with the work of the Chinese potter.

What is Salt glaze?—We know that many of the stoneware Bellarmines and Rhenish jugs were glazed with salt. It was a process known on the Continent at a very early date, some authorities place it as early as the twelfth century. But it was not until the second half of the sixteenth century that German and Flemish potters used this salt glaze to any great extent. We have seen, in the chapter on stoneware, that the appearance in the mottling and in the orange-skin-like surface is due to the action of salt glaze.

To cover pottery with an outer surface has been practised from earliest times either by the use of some glassy material or by powdered lead. Glazing with common salt was quite a new departure by the English potters. In order for this salt glaze to be used there must be a very high temperature, so high, as a matter of fact, that it would melt or soften in the kiln most English earthenware. This is where stoneware in its body differs from earthenware; it is what is termed "refractory," that is to say, it is not readily fusible. Stoneware is not always glazed. Elers did not glaze his red ware, and Wedgwood did not glaze his basalt or black ware. Stoneware can also be glazed with other processes than the salt glaze, but, as a rule, stoneware is associated with salt glaze.

Without entering too tediously into the exact steps by which salt glazing is performed, it may be roughly described as follows. Other glazes, such as lead, are applied to the surface of the ware prior to its entry into the kiln for firing, but in salt glaze the glaze is incorporated with the ware while it is actually in the kiln. Towards the end of the firing common salt (chloride of sodium) is thrown into the kiln, which is packed with the ware, through apertures in the kiln which has to be specially designed for salt-glaze use. At the high temperature of the kiln (about 2,190° Fahr.) the salt is volatised and its vapour penetrates the saggers (that is, the earthen vessels containing the pieces being made), which have perforated sides to enable this vapour to form on the surface of the pieces being fired. This vapour chemically unites with the silica largely present in the body of the stoneware, and forms a silicate on the surface of the ware. That is to say, the stoneware becomes coated with a thin layer or glaze of sodic silicate or soda-glass.

GROUP OF SALT-GLAZED WARE.
Jug enamelled in colours. Teapot blue enamel by Littler.
(In the collection of Col. and Mrs. Dickson.)

This chemical action taking place simultaneously with the final firing of the ware before its removal from the kiln incorporates the glaze with the body of the ware itself. It is this combination which causes the minute depressions or tiny pin-holes in all stoneware from Bellarmines down to the finely and nearly translucent salt-glazed Staffordshire ware which has a surface like that of leather. The same multitudinous pin-hole surface is characteristic of Oriental porcelain, which like stoneware is fired at a very high temperature, and the glaze and the body completed at one firing in the grand feu. Though, of course, this is not salt glaze, nor is the surface other than as smooth as glass to the touch, although under a strong glass or even to the naked eye these pin-holes are easily discernible.

At the present day salt glaze is mainly used for such ware as ink-pots, drain pipes, insulators for telegraphic instruments, and common ginger-beer bottles. The connection between John Dwight, of Christ Church, Oxford (Master of Arts), the creator of the magnificent bust of Prince Rupert, the glory of the ceramic collection at the British Museum, and between John Philip Elers, godson of Queen Christina, and this sad array of utilitarian nondescripts, is not a pleasing subject for reflection. It is sad to think that these triumphs have been won in vain by the genius of the old potters over the plastic clay. What an ignoble ending to the long chain of experiments! When Dwight destroyed his secret memoranda it is as though he foresaw the era of the drainpipe.