Scientific Intelligence — Arts. 187 



ARTS. 



13. On Auriferous Olass. By H. Rose. — Gold is well known 

 to be used in making a beautiful red glass. After fusion this glass 

 is colourless ; but when heated not above a red heat, it becomes of a 

 bright-red colour. Rose suggests that the gold is contained in the 

 glass in the state of a protoxide, which forms a colourless silicate by 

 fusion, but sets free some portion of the protoxide when re-heated to 

 a temperature a little below that which forms it. This protoxide 

 disseminated in a small quantity, in an extreme state of subdivision, 

 is believed to give the red colour. When too much heated, the red 

 changes to a brown, and Hose attributes this to the oxide of gold be- 

 coming partly reduced, and metallic gold set free. A fact, accord- 

 ing to Hose, confirming this view, is presented by copper. For a 

 glass containing the protoxide of copper is colourless after fusion, a 

 silicate being formed ; but it becomes green after heating, owing to 

 the oxide set free. The ingredients used for the auriferous glass are, 

 forty-six pounds of quartz, twelve of borax, twelve of nitre, one of 

 minium, and one of arsenous acid ; these are moistened with a solu- 

 tion of eight ducats of gold, in aqua regia, and then fused. — Pog^ 

 gendorf^ Annal.^ vol. Ixxvii., p. 556.) 



14. On a Peculiar Property of Coke. By Mr J. Nasmyth. — 

 The following interesting fact was discovered some years ago, and it 

 appears to furnish additional evidence as to the identity of the dia- 

 mond with carbon ; namely, that coke is possessed of one of the most 

 remarkable properties of the diamond, in so far as it has the pro- 

 perty of cutting glass. I use the term '' cutting" with all due con- 

 sideration, in contradistinction to the property of scratching, which 

 is possessed by all bodies that are harder than glass. The cut pro- 

 duced by coke is a perfect clear diamond-like cut, so clean and per- 

 fect as to exhibit the most beautiful prismatic colours, owing to the 

 perfection of the incision. Coke hitherto has been considered as a 

 soft substance, doubtless from the ease with which a mass of it can 

 be crushed and pulverised ; but it will be found that the minute plate- 

 formed crystals, of which a mass of coke is composed, are very 

 hardy and, as before said, are possessed of the remarkable property 

 of cutting glass. This discovery of the extreme " diamond-like"* 

 hardness of the particles of coke will, no doubt, prove of value in 

 many processes in the arts, as well as interesting in a purely scien- 

 tific sense. In a conversation which ensued, it was stated by Mr 

 Chance of Birmingham, that, in all probability, the knowledge of 

 this fact would lead to a saving of nearly £400 a-year, in their esta- 

 blishment alone. 



15. On the Chemical Character of Steel. By Mr Nasmyth. 



Were we to assume, as our standard of the importance of any inves- 

 tigation, the relation which the subject of it bears to the progress of 

 civilisation, there is no one which would reach higher than that which 

 refers to the subject of steel ; seeing that it is to our possession of 



