182 PHILOSOPHICAL TRANSACTIONS. [ANNO 1782. 



commerce; and should expect from their wonted assiduity and liberal disposi- 

 tion of proper rewards for the culture and manufacture of so valuable a com- 

 modity, to see it as successfully carried to perfection as several other branches 

 have happily attained by their care and protection; and shall think myself very 

 happy in being any ways instrumental in forwarding so good a purpose. 



VI. On some Scoria from Iron JVorks, which resemble the Vitrified Filaments 

 described by Sir William Hamilton. By Samuel More, Esq. p. 50. 



In the account given of the eruption of Mount Vesuvius in August, 1/7Q, 

 by Sir Wm. Hamilton, printed in the Philos. Trans., vol. 70, p. 42, et seq. 

 among many other equally curious informations, it is said, " Long filaments of 

 vitrified matter, like spun-glass, were mixed with and fell with the ashes." And 

 in a note annexed it is also said, that " during an eruption of the volcano in the 

 isle of Bourbon in 1766, some miles of country, at the distance of 6 leagues 

 from the volcano, were covered with a flexible capillary yellow glass, some of 

 which were 2 or 3 feet long, with small vitreous globules at a little distance one 

 from the other." 



There appeared to me, on reading these passages, an exact similarity between 

 these productions of the 2 volcanos and some scoria I had received from a worthy 

 friend, who is master of one of the largest works in England for smelting, iron. 

 In a letter accompanying the specimen, he writes, " I have sent a specimen of some 

 slag, or vitrified cinder, which has by the reverberation of the blast from the 

 Tweer,* been drawn out while fluid into long cobweb-like threads, sometimes 10 

 or 12 feet in length, and affixed itself to the beams, &c. of the bellows room." 



Whoever has attentively viewed the large furnaces where iron ore is smelted 

 by coke, will readily allow, that they present the most striking resemblance, 

 however diminished, of that most tremendous of all appearances, the eruption 

 of a volcano ; and that the most exact pictures hitherto seen of the flowing of the 

 lava from the one, is shown by the running of the slag from the other : this has 

 induced me to send, for the inspection of the r. s., some of the scoria in its 

 capillary state, and with all due deference to the acknowledged abilities of Sir 

 William Hamilton, to submit, whether the fine filaments may not be produced 

 in the eruption of the great furnaces of nature, by means similar to those by 

 which we see them formed in the furnaces of art. Sir William seems to think, 

 " That what he calls the natural spun glass which fell at Ottaiano, as well as 

 that which fell in the Isle of Bourbon in 176O, must have been formed, most 

 probably, by the operation of such a sort of lava as has been just described 

 (that is, perfectly vitrified) cracking, and separating in the air at the time of its 



* The Tweer is that opening through which the air is driven by the bellows into the body of the 

 furnace. 



