$26 PHILOSOPHICAL TRANSACTIONS. [anNO 17 5g, 



&c. ; and that only calcination discharges them. Therefore it is probable that 

 Mr. Chambers's method of staining or colouring marbles is extremely good. 



Though acid menstrua work greatly on marble, yet it is observable that these 

 colours are not discharged by them, but only by calcination ; which, as it en- 

 tirely and thoroughly destroys the compages of the stone, the substances of the 

 colours must undoubtedly at the same time be exhaled by the force of the fire. 

 We observe a like process in the works of nature ; viz. in the dendritae, or such 

 as are on alkaline stones : for though the stones are utterly corroded by the acids, 

 yet the dendritae, however merely superficial, remain ; but if calcined, the said 

 dendritae are immediately exhaled, and entirely disappear. 



This art will not only give pleasure to the eye by regular paintings (whereas 

 the natural colourings of marble are very irregular) but it may be very useful to 

 blazon arms, and for inscriptions ; as sculpture alone can never express colours, 

 and chisseled inscriptions, &c. suffer much by age; for probably a monument of 

 marble, rightly coloured by this method, will be preserved many ages from the 

 injuries of the weather, though at the same time the stone itself will be some- 

 what hurt or corroded by the air. 



F'l. Observations on the Sea Scolopendre, or Sea Millepes.* By John j4ndrew 

 Peyssonel, M. Z)., F. R. S. Translated from the French, p. 35. 



This creature, in its figure, is like the land scolopendre, or, as Pliny says, to 

 the hairy caterpillar, commonly called the milleped animal. It is of the same 

 colour, has the same arrangement of circular rings; but whereas the land scolo- 

 pendre is fiat, this is square. Dr. P. counted 80 rings, which form the body 

 and head, when brought to him. This sea insect was very small, and almost 

 imperceptible. He was surprised, after having kept it some time, to see a round 

 body, of a blackish green colour, like the glans virilis, pass out of it, which had 

 a considerable opening, like the canal of the urethra. This gland was sur- 

 rounded by two bodies or bowels, which appeared in form of a prepuce turned 

 back; the one was yellowish, and the other whitish; each but a line thick, 

 stronger and larger above, and terminating below like a ligature, filled with a 

 matter like that contained in the intestines of fishes and insects. This may be 

 what gave occasion to Pliny, and other naturalists, to think, that these insects, 

 finding themselves taken, throw out their bowels in order to lessen their bulk. 



The body of the animal is square; and the 4 sides are armed with such prickles 

 as he never saw before. Also every ring has 4 bundles of prickles. The fol- 

 lowing is the manner of their being disposed: at the end of each ring, above 

 the square, on each side we see a gland, near which a bundle of prickles arises 



* The animal here described seenii to belong to the genus terebella. 



