142 plint's NATUEAL HISTOET. [Book XXXIII. 



however, is submitted to a dyeing process, it being boiled with 

 aplant^^ used pafticularly for this purpose, ^^ and imbibing its 

 juices. In other respects, the mode of preparing it is similar 

 to that of chrysocolla. From caeruleum, too, is prepared the 

 substance known as " lomentum,"^^ it being washed and 

 ground for the purpose. Lomentum is of a paler tint than 

 cseruleum ; the price of it is ten denarii per pound, and that 

 of cseruleum but eight. Cseruleum is used upon a surface 

 of clay, for upon lime it will not hold. A more recent 

 invention is the Vestorian^^ caeruleum, so called from the 

 person who first manufactured it : it is prepared from the finer 

 parts of Egyptian cseruleum, and the price of it is eleven 

 denarii per pound. That of Puteoli is used in a similar 

 manner, ^^ as also for windows :^^ it is known as " cylon." 



** cseruleum." " Pliny clearly adds to it an artificial colour, whicli in my 

 opinion was made in the same manner as our lake ; for he speaks of an 

 earth, which when hoiled with plants^ acquired their blue colour." — Hist. 

 Inv., Vol. II. p. 480. 



^^ Supposed by Hardouin to have been " glastura " or " woad," the Isatis 

 tinctoria of Linnaeus, mentioned in B. xxii. c. 2. 



^2 " In sua coquitur herb^." 



^3 A blue powder ; see Chapter 27 of this Book. Beckmann has the 

 following remarks on this and the preceding lines : •' The well-known 

 passage of Pliny in which Lehmann thinks he can with certainty discover 

 cobalt, is so singular a medley that nothing to be depended on can be 

 gathered from it. The author, it is true, where he treats of mineral pig- 

 ments, seems to speak of a blue sand which produced different shades of 

 blue paint, according as it was pounded coarser or finer. The palest powder 

 was called lomentum, and this Lehmann considers as our powder-blue. I 

 am, however, fully convinced that the cyanus of Theoplirastus, the cceruleum 

 of Pliny, and the chrysocolla (see Chapter 26), were the blue copper earth 

 already mentioned, which may have been mixed and blended together.'' — 

 Hist. Inv. Vol. I. pp. 480, 48L Bohn's Edition. 



^* According to Vitruvius, B. vii. c. 11, the manufactory of Vestorius 

 was at Puteoli, now Pozzuoli. This was probably the same C. Vestorius 

 who was also a money-lender and a friend of Atticus, and with whom 

 Cicero had monetary transactions. He is mentioned as " Vestorium meum," 

 in the Epistles of Cicero to Atticus. 



15 For colouring surfaces of clay or cretaceous earth. This kind was also 

 manufactured by Vesturius, most probably. 



1^ •' Idem et Puteolani usus, praeterque ad fenestras." " The expression 

 here, urns ad fenestras^ has been misapplied by Lehmann, as a strong proof 

 of his assertion ; for he explained it as if Pliny had said that a blue pig- 

 ment was used for painting window-frames ; but glass windows were at 

 that time unknown. I suspect that Pliny meant to say only that one 

 kind of paint could not be employed near openings which afforded a 



