402 Rev. W. V. Vernon's Chemical Examination uj' a 



over the platinum; when ignited with carbonate of soda in the 

 exterior flame of a candle, the globule remained uncoloured*. 



Acids dissolved the powder entirely and without efFerves- 

 cence, though with a perceptible smell of sulphuretted hydro- 

 gen. The excess of acid being driven off) water redissolved 

 the whole f. The solution was precipitated white by ammonia, 

 an excess of which again took up the precipitate ; it was also 

 precipitated white by the ferro-prussiate of potash, and by the 

 sulphuret of ammonia. A solution of a grain, from which the 

 sulphuret had been thrown down, was evaporated and ignited, 

 and when the ammoniacal salt was driven off", there was no 

 residue. 



From these experiments I was led to conclude that the sub- 

 stance is oxide of zinc in a state of purity, and uncombined 

 with any of those substances with which as a mineral it has 

 been hitherto found united, excepting only a minute and inap- 

 preciable quantity of sulphur; and I was confirmed in that con- 

 clusion by the following experiment with which I terminated 

 my examination. I put a crystal into a solution of bisulphate 

 of potash ; it dissolved quietly and entirely ; I left the solution 

 to crystallize, and found all the crystals that were formed to be 

 right rhombic prisms, which I recognised as the compound 

 sulphate of potash and zinc. 



It is worth while to observe how nearly this substance and 

 the natural ore of zinc, in which the oxide, though not abso- 

 lutely purej, has been found in the simplest state, resemble 

 one another in specific gravity and in crystalline form. The 

 specific gravity of the red oxide of zinc found at New Jei'sey 

 in America, is stated to be 6-2; and the late Mr. William 

 Phillips has deduced from the cleavage of this mineral, (as it is 

 met with in an incompletely crystallized state,) the form of a 

 regular hexagonal prism. So that the mineral-laboratory of 

 nature seems to have been employed in forming the same cry- 

 stal which the crucible has here produced in a more perfect 

 form ; and thus the substance before us adds another instance 

 to those already known, of the mineralogical presumption, that 

 the agency of fire may have been concerned in the formation of 

 mineral veins, or in the structure of at least some of the rocks. 



I will take this opportunity of communicating also to the 

 Society the result of some experiments which I have made on 

 the ancient glass beads, lately presented by the Rev. Mr. Stil- 



' It contained therefore no manganese. 



f It contained therefore no silica, nor any notable quantity of sulphur, 



X It is coloured by a small quantity of manganese. 



linefleet. 



