342 PROFESSOR HEDDLE ON 



species, such as felspar, mica, talc, and asbestos, he instituted a family which he termed 

 Hombarg (the Roche de Come of the French) ; this embraced, as a sub-family, Skiorl 

 (Schorl of the Germans). 



Cronstedt (1758) adopted the same family, and threw into it, "as a convenient 

 pocket," many of the recently discovered species. 



It is not altogether easy to make out what species were entitled to get into this 

 pocket, or which side of its medial partition it was intended that they should lodge 

 themselves in, beyond this that comeus was to hold " cheap or worthless stones," 

 " mostly of colours from black to dull green." 



Cronstedt introduced a little more method as regards the " Skorl" side of the 

 pocket, making it nearly synonymous with the comeus crystallisatus of Wallerius, 

 and destined to receive prismatic minerals of black, brown, green, and reddish colours, 

 but still having some resemblance to horn in lustre. 



He, however, again introduces confusion — a confusion which was continued by 

 Wallerius in an edition of 1778 — through adopting the term "Basaltes" instead of 

 Skorl; and Hill, in his work on Fossils, 1771, fortifies the error, when, in speaking of 

 the Shirts, he says, "as to size we see them from that of barleycorn up to the Giant's 

 Causeway," the columns of which he calls "Basaltes Hibernicus" or "Irish Shir]." 



Romes de Lisle, however, in 1783, bringing crystallography to bear, at once got rid 

 of such excrescences as basaltic pillars, helleflintas, and rocks ; but on account of 

 chemistry being still a lagging science, he was forced to throw in many new and indeed 

 old species, and to increase the number of adjective distinctions ; and though we do! 

 find these to be all Silicates, yet he departs from the prismatic elongation by introcluc-: 

 ing such species as axinite, staurolite, and harmotome. 



When chemistry came to lend a hand to the structural erection of the science, 

 the disintegration of the great "schorl group" commenced. Bergmann, by his 

 researches, published in 1780, went far to disband it ; the five which lingered last wen 

 kyanite, " blue schorl " ; staurolite, "cruciform schorl"; andalusite, "a red schorl" 

 rutile, red schorl ; tourmaline, black schorl ; and these were extruded from the famil 

 in the above order. There is this much indication of these forming a natural grou 

 that, with the exception of rutile, they are all silicates of alumina. 



It is somewhat singular that the substance — namely, tourmaline — which last retaine 

 the name schorl seems to have been that to which the term was first applied. I 

 Matthesius' Sarepta, 1562, we find that the name " schurl" was used for the "steril 

 black little stones" accompanying tin ore and gold, and which were thus probabl 

 tourmaline ; and as they were metallurgically worthless, it has been suggested that tl 

 word originally was derived from the old German word Schor, meaning refuse. 



" Schorl " is a name still applied to an inferior fibrous, opaque, black tourmalins ; 

 is the sole representative of a great family ; but we still use the adjective schorlous—\> 

 " schorlous beryl " — to imply crystals, thinner and more elongated than usual, which i 

 imbedded in a matrix with more or less of a radiating arrangement. 



