252 FHILOSOPHICAL TRANSACTIONS. [aNNO 1685. 



Observations on the Purple Fish.* By Mr. JVm. Cole, of Bristol. 



N° 178, p. 1278. 



Mr. Cole having been informed that a certain person, Hving by the sea-side 

 in some port or creek in Ireland, made considerable profit, by marking with a 

 delicate durable crimson colour, fine linen of ladies or gentlemen, sent from 

 many parts of that island, with their names, or otherwise as they pleased : 

 he made experiments on all the shell-fish taken on the coasts near him, till at 

 length he obtained that delicate colour. 



The whole process, discovered by often repeated experiments, was as follows : 

 These shells being harder than most of other kinds, are to be broken with the 

 smart stroke of a hammer, on a plate of iron, or firm piece of timber, with 

 their mouths downwards, so as not to crush the body of the fish within ; the 

 broken pieces being picked off, there appears a white vein, lying transversely 

 in a little furrow or cleft, next to the head of the fish, which must be digged 

 out with the stifle point of the horse-hair pencil made short and tapering. 

 The letters, figures, or what else shall be traced on linen or silk, as much 

 forced in, as it can be by the pencil, will presently appear of a pleasant light 

 green colour ; and if placed in the sun, it will change into the following 

 colours ; i.e. if in winter, about noon, if in the summer, an hour or twd 

 after sun rising, and so much before setting ; for in the heat of the day, in 

 summer, the colours will come on so fast, that the succession of each 

 colour will scarcely be distinguished, viz. it will change from a light green 

 to a deep green ; and then in a few minutes to a full sea-green ; after which, 

 in a few minutes more, it will become of a Watchet blue; and from that, 

 in a little time more, it will be of a purplish red : after which lying an 

 hour or two more, supposing the sun still shining, it will turn to a very 

 deep purple red, beyond which the power of the sun cannot further alter it. 

 And note that these changes are made faster or slower, according to the de- 

 grees of the sun's heat. But the last and most beautiful colour, after washing 

 in scalding water and soap, after again exposing the matter to the sun or wind 

 to dry, will be a different colour from all those before-mentioned, i. e. of a fair 

 bright crimson, or nearly of the prince's colour, which, though no styptic be 

 used to bind the colour, will continue the same, if well managed ; as has been 

 found in handkerchiefs, that have been washed more than 40 times ; only it will 



* The animals of several thelltof the Linnsean genera of buccinum and murex, afford a purple dye, 

 and were used by the ancients in the preparation of their most valuabl* vestments. The species here 

 described is the btKcinwn tapillus of Linnaeus, a very common shell on most of the European coasts. 

 It is unnecessary to add, that the introduction of cochineal has long superseded the use of these 

 kinn of dyes. 



