1823.] Philosophical transactions for \S2S, Part L '^23 



" Their hardness also is totally different from that of pyrites, 

 and is such as, when combined with the preceding characters, 

 marks a substance wholly unknown to mineralogists. By se- 

 lecting 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 

 on rock-crystal. 



" Having broken out some of these crystals for experiment, 

 I found them all apparently attracted by a magnet; but observ- 

 ing 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 decep- 

 tive appearance of magnetism. 



" Before the blow-pipe they are utterly infusible. A con- 

 tinued heat oxidates them, and they become purple or red at 

 the surface, according to the degree of oxidation, or depth to 

 which it penetrates."' 



We must here add to Dr. Wollaston's statement respecting 

 the purity of these cubes of titanium, as given in our report 

 of this paper, that they contain no sulphur. 



In considering the properties which evince that they are in a 

 metallic state, Dr. W. observes, that when the action of nitre 

 upon them is rapid, " heat is evidently generated, as by the 

 combustion of other metals ; but as I acted upon them in their 

 solid state, and did not pulverise them, I did not witness what 

 could properly be called detonation, as described by Lampadius." 



To the several metals with which Dr. Wollaston was unsuc- 

 cessful in his endeavours to unite one of these cubes, as al- 

 ready mentioned by us, we must now add lead. The following 

 particulars form an appendix to this interesting paper. 



^^ Since the date of this communication, the liberality of 

 Mr. Anthony Hill, of Merthyr Tydvil, has supplied me with a 

 larger quantity of the slag which formed the subject of my first 

 experiments, and has enabled me to determine the specific 

 gravity of metaUic titanium to be 5*3. For this purpose, the 

 vitreous part was fused with a mixture of borax and sub-carbo- 

 nate of soda in about equal quantities, and was then dis- 

 solved in muriatic acid, which also removed a quantity of me- 

 tallic iron, and left the titanium freed from extraneous matter. 

 Though great part of what was thus obtained from the interior 

 of the slag was in a pulverulent state, the quantity, which 

 amounted to 32 grains, and displaced 6*04 of water, was suffi- 

 cient to preclude any considerable error. 



" I have moreover learned that metallic cubes, similar to 

 those which I have above described and examined, were, more 

 than 20 years since, observed in a sla^ at the Clyde Iron 

 Works in Scotland ; that a small quantity has also been met 

 with at the Low Moor Iron Works, near Bradford, in York- 

 shire ; ' and at the Pidding Iron Works, near Alfreton, in Dei- 

 byshire ; and that some good specimens have been obtained 



