M2 PLINY'S NATURAL HISTOIIT. [Book XXXIII. 



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

 a plant 11 used particularly for this purpose, 12 and imbibing its 

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

 to that of clirysocolla. From ctcruleum, too, is prepared -the- 

 Hibstance known as " lomentum," 11 it being washed and 

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

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

 of caerulcum but eight. Cacruleum is used upon a surface 

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

 invention is the Vestorian 11 cjcruleum, so called from the 

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

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

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

 manner, 15 as also for windows : 18 it is known as " cylon." 



" csenileum." " Pliny clearly adds to it nn artificial colour, -which in my 

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

 earth, which when l>oiled with plants, acquired their blue colour." Hist. 

 Jnv., Vol. II. p. 4 SO. 



11 Supposed by Hardouin to have been " glastum '* or " woad," the Isatis 

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



ls ** In sua. coquitur herba." 



13 A blue powder; soe Chanter 27 of this ISook. Beclcmann has the 

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

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

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

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

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

 blue paint, according as it was pound* d coarser or finer. Tho palest powder 

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

 am, however, fully convinced that the eyxtius of Theophrasttis, the fttrulcitm 

 of Pliny, and the chrysocolfa (see Chapter 2G), were the bluo copper earth 

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

 Jlist Inv. Vol. I. pp. 4SO, 481. Jlohns Edition. 



11 According to Vitruvius, B. vii. c. 11, the manufactory of Vefitorius 

 "was at Putt-oH, 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, lie is mentioned as " Vesr.orium 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. 



15 Idem et Puteolani usus, prtcterque ati fenestrfts." "The expression 

 hcrp, w?5 adfcncstras, has been misapplied by Lehmann, ns a strong proof 

 of bis 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 eay only that one 

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



