To render cloth perfectly white, it was also fumigated with sulphur by the fullers, who were not ignorant that many colours were destroyed by its vapours[269]. We are told by Apuleius that the wife of a scourer concealed her gallant under a vessel of basket-work, over which cloth used to be laid to whiten by the effects of sulphur kindled under it. Our washer-women employ a cask in this mode of bleaching, and our clothiers a small close apartment, in which the wet cloth is suspended upon hooks.
Pliny has described the method of washing used at Rome, but many things respecting it appear to me obscure[270]. The cloth was first washed with Sardian earth; it was then fumigated with sulphur, and afterwards rinsed with real Cimolian earth. The word _desquamatur_ was undoubtedly a term of art, which cannot be further explained, because we are unacquainted with the operation to which it alludes. Pliny seems to have been particular in mentioning real Cimolian earth, because the false kind became black by the steam of the sulphur which the cloth absorbed. Was it adulterated with some metallic oxide or with white lead? It was dear enough to induce people to mix it with such articles; and in that case it must necessarily have become black.
The expression _funditur sulphure_ seems to be attended with no less difficulty. In comparing the different readings, I find that the oldest editions have _offunditur_, which has been changed into _effunditur_, and lastly into _funditur_. It is probable however that instead of _offunditur_ we ought to read _offenditur_, which would make the whole clear. I am much surprised that this reading was not adopted by Hardouin. As Pliny says in other parts of his work “offendit stomachum,” and “offendit aciem oculorum,” he might undoubtedly have applied that word to the earth and its colour.
Fast colours, which the acid of sulphur might render pale, but could not entirely destroy, would by washing with Cimolian earth be improved or rather restored, as the earth would absorb and carry off the acid. There was also another kind of earth (_saxum_) which was useful in the preparation of cloth fumigated with sulphur, but which injured the dye, probably because it was too calcareous, and which was perhaps our common chalk.