18 
Dr. Wollaston on metallic titanium. 
My attention has been directed, by various friends, especially 
by Professor Buckland, who gave me the subject of my ex- 
periments, to certain very small cubes, having the lustre of 
burnished copper, that occasionally are found in the slag of the 
great iron-works at Merthyr Tydvil, in Wales, which, from 
their hue, have, by some persons, been imagined to be pyritical. 
Their colour, however, is not truly that of any sulphuret of 
iron that I have seen ; and though the form be cubic, it is not 
the striated cube of common iron pyrites, which so often passes 
into the pentagonal dodecahedron, but similar to that of com- 
mon salt ; for any marks, that are to be discerned on their 
surfaces, appear as indented squares instead of striae. 
Their hardness also is totally different from that of py- 
rites, and is such as, when combined with the preceding cha- 
racters, marks a substance wholly unknown to mineralogists. 
By selecting a sharp angle of one of these cubes, I found that 
I could not only write upon the hardest steel, or upon crown 
glass, but could even visibly scratch a polished surface of 
agate or rock crystal. 
Having broken out some of these crystals for experiment, 
I found them all apparently attracted by a magnet ; but ob- 
serving that they had still small portions of slag adherent to 
them, they were next digested in muriatic acid, which, by 
dissolving the iron from their surfaces, soon freed them from 
their deceptive appearance of magnetism. 
The cubes thus purified are not acted upon by muriatic acid. 
Nitric acid has no action upon them. 
Nitro-muriatic acid does not dissolve them. 
Boiling sulphuric acid does not affect them. 
Before the blow-pipe they are utterly infusible. A con- 
