VOL. XLIV.]] PHILOSOPHICAL TRANSACTIONS. 287 



In some of these stones, several curious veins, of a red and bluish colour, are 

 very remarkable, being intermixed with black and white striae. Having broken 

 some of them, he found in the inside a kind of white, and several clusters of 

 small white and black angular crystals, which through the microscope appear 

 transparent, and of different shapes, but mostly hexagonal. He discovered such 

 crystals in some of the woody part of these stones. 



One piece of a white stone he calcined in a crucible for 24 hours, but could 

 neither reduce it to coal nor lime. The powder yielded faintly to the magnet. 

 This stone was found in the ground at some distance from the lake. One piece 

 of a black stone, found in the lake, he likewise calcined for 24 hours, and could 

 not reduce it to coal or lime : the powder yielded briskly to the magnet. He 

 calcined one piece of another stone, about one inch thick, for about 4 hours, in 

 an intense fire, till it grew as red as it could be, when he took it out of the cruci- 

 ble. He observed several veins, not discernible before, of a ferruginous matter, 

 about -fV of an inch thick, and when reduced to powder, it applied strongly to 

 the magnet. 



In other stones he found some veins of wood, about 1 and 2 inches thick, no 

 way petrified, though the stones were every way so outwardly. Some of that 

 woody part he also burnt in a crucible; it emitted a bluish flame, as if impreg- 

 nated with sulphur, and had the strong smell of burning charcoal. When burnt 

 to a coal, and reduced into powder, it faintly yielded to the magnet. 



He calcined another of these stones, weighing 1 oz. 13 dwts. 12-|-gr.; after 

 burning 4 hours it weighed only 1 oz. 10 dwts. 8|gr. and lost 3 dwts. 4 gr. ; 

 which proceeds probably from unpetrified veins of wood in the heart of the stone, 

 which were destroyed by the fire, as in the crucible it emitted now and then a bluish 

 flame, like brandy when burning. This storie, when taken out of the crucible, 

 and cooled, had the colour of iron, when heated in, and cooled from the forge. 



Part of another stone, which, by visible veins of ore, appeared to contain a 

 good deal of iron, he likewise calcined for 4 hours; the powder yielded most sur- 

 prisingly to the magnet ; so that it appears, that the opinion of Nennius, Boetius, 

 and other ancient writers, was not absolutely destitute of foundation. 



The white wood-stones are generally found in the ground at 2, 4, 6, and 8 

 miles distance from the lake, and sometimes very deep in the earth. The black 

 ones are always found in the water, or on the shores of the lough; sometimes at 

 the mouths of rivers or rivulets that empty themselves into it ; but those with 

 wood continuous have not yet been found above 20 yards distance from the water 

 of the lake; that is, where the water reaches in the winter, or at other times. 



Some of these stones are outwardly covered with a thin white substance, which 

 has run through the pores of that part of the stone that was exposed to the air, 

 and not covered by the water, mud, or clay ; and on some others it is rather an 

 incrustation of that white substance, which he takes to be the slimy, unctuous, 



