The actual tints produced from the shell-fish appear to have ranged from blue, through violet and purple, to crimson and rose.[824] Scarlet could not be obtained, but was yielded by the cochineal insect. Even for the brighter sorts of crimson some admixture of the cochineal dye was necessary.[825] The violet tint was not generally greatly prized, though there was a period in the reign of Augustus when it was the fashion;[826] redder hues were commonly preferred; and the choicest of all is described as “a rich, dark purple, the colour of coagulated blood.”[827] A deep crimson was also in request, and seems frequently to be intended when the term purple ({porphureos}, _purpureus_) is used. A third industry greatly affected by the Phoenicians was the manufacture of glass. According to Pliny,[828] the first discovery of the substance was made upon the Phoenician coast by a body of sailors whom he no doubt regarded as Phoenicians. These persons had brought a cargo of natrum, which is the subcarbonate of soda, to the Syrian coast in the vicinity of Acre, and had gone ashore at the mouth of the river Belus to cook their dinner. Having lighted a fire upon the sand, they looked about for some stones to prop up their cooking utensils, but finding none, or none convenient for the purpose, they bethought themselves of utilising for the occasion some of the blocks of natrum with which their ship was laden. These were placed close to the fire, and the heat was sufficient to melt a portion of one of them, which, mixing with the siliceous sand at its base, produced a stream of glass. There is nothing impossible or even very improbable in this story; but we may question whether the scene of it is rightly placed. Glass was manufactured in Egypt many centuries before the probable date of the Phoenician occupation of the Mediterranean coast; and, if the honour of the invention is to be assigned to a particular people, the Egyptians would seem to have the best claim to it. The process of glass-blowing is represented in tombs at Beni Hassan of very great antiquity,[829] and a specimen of Egyptian glass is in existence bearing the name of a Usurtasen, a king of the twelfth dynasty.[830] Natrum, moreover, was an Egyptian product, well known from a remote date, being the chief ingredient used in the various processes of embalming.[831] Phoenicia has no natrum, and not even any vegetable alkali readily procurable in considerable quantity. There _may have been_ an accidental discovery of glass in Phoenicia, but priority of discovery belonged almost certainly to Egypt; and it is, upon the whole, most probable that Phoenicia derived from Egypt her knowledge both of the substance itself and of the method of making it.