33G On the Gas Blowpipe. 



Clark, Pure Oxide of Magnesium (Magnesia). 

 Fusion psr se, extremely difficult. When the earth is made 

 to adhere (by moisture with distilled water and subsequent de- 

 siccation) and placed upon charcoal, it is fusible into a whitish 

 glass ; but the parts in contact with the charcoal acquire an im- 

 posing pseudo-metallic lustre with a purple coloured flame. 



Clark. Hydrate of Magnesia (pure foliated Magnesia from 

 America). 



" This substance is incomparably refractory; with the utmost 

 intensity of the heat of the gas blowpipe, it is ultimately reduci- 

 ble to a white opake enamel invested with a thin superficies of 

 limpid glass. Its fusion is accompanied with a purple coloured 

 flame." 



Experiments on Corundum. 



Silliman, page 112. " Corundum of the East Indies was ivi- 

 viediately and perfectly fused into a grey globule." " Corundum 

 of China the same with active ebullition." 



Clark, page 56. " Common corundum (greenish grey crystal- 

 lized primary corundum from the East Indies), JiwiWe, h^it witli 

 difficulty, into a greenish coloured translucent glass nearly trans- 

 parent, which at last becomes melted into a bead-like form ; or 

 otherwise exhibits upon its surface minute cavities caused by the 

 escape of gas during its fusion. This gas is probably the same 

 which pure silica more abundantly exhibits. A slightly coloured 

 greenish flame accompanies the fusion of corundum." 



Experiments on Sappar. 



Silliman. " Sappar or kyanite perfectly and instantly fused 

 with ebullition into a white enamel." 



Clark, page 57. " This mineral, owing to its refractory nature, 

 was used by Saussure as a supporter in experiments with the 

 common blowpipe. It fuses very readily into a snow white frothy 

 enamel." 



Experiments on Zirco?i. 



Silliman, page 112. "Zircon and Ceylon melted with ebul- 

 lition into a white enamel." 



Clark, page."*8. " One of the most refractory substances; ex- 

 posed to the heat of the gas blowpipe, it becomes first opaque and 

 of a white colour ; and afterwards its superficies undergoes a 

 partial fusion, and exhibits a white opake enamel resembling 

 porcelain*. 



Experiments on the Spinelle Ruby. 



Silliman, page 112. " Spinelle ruby fused immediately into 

 an elliptical red globule." 



* I might say here v.-ith tnit'i, Professor Claik in England was unable to 

 fuse zircon in his mode of operating with tlie gas blowainc. 



Clark, 



