108 Dr. Mac Culloch's Sketch of the 



present corroded and tarnished state of the surfaces of these statues 

 we cannot trace the nature or the defects of this variety, but an 

 examination of its texture and composition in the broken frag- 

 ments, serves to excite the deepest regret, that the genius of the 

 greatest sculptor whom the world has seen, should for want of 

 better materials have been condemned to bestow its energies on so 

 perishable and so defective a stone. This marble is of a loose 

 texture and moderate sized grain, coarser than that of Carrara, but 

 finer than that of Paros ; in colour it is exceedingly imperfect, 

 being tinged with gray, brown, and yellow, and mottled with 

 transparent parts, which give it the appearance of having been 

 stained with oil. But its most formidable defect is its laminated 

 structure, and the quantity of mica with which it is contaminated : 

 to this we are to attribute the corrosion and almost entire ruin of 

 so many of the specimens, the action of the weather dissolving 

 those parts of the stone where the mica is most abundant, and 

 eating deep fissures through many parts of the work. It is pe- 

 culiarly unfortunate that the two most admirable specimens, spe- 

 cimens which are calculated to excite in the minds of artists a 

 mixed feeling of wonder and despair, the horse's head and the 

 Theseus, should be those which have suffered most. Had they 

 been fortunately executed in the more uniform and durable stone of 

 Carrara, these works might still have been preserved to us in all 

 their original perfection of drawing and surface. Even the ham- 

 mer of the Turk would have rebounded with little injury from 

 the marbles of this texture, while the micaceous stone of Pente- 

 licus splitting in the direction, of its laminae, has permitted the 

 complete mutilation of many valuable sculptures. 



We have no geological information with regard to the relations 

 of, these stones. The great resemblance of the Pentelic marble to 



