ANNO 1681-2.] PHILOSOPHICAL TRANSACTIONS. 517 



powder, and having first wiped over the figure with the white of an egg, sprinkle 

 upon it this powder, which will shine as the stone. 



This sort of furnace is not absolutely necessary, but it is convenient as well 

 in determining the time, as the degree of heat ; for if too great, it will destroy 

 the quality; if too little, it will not raise it. 



Prattica minerale del Marchese Marco Antonio della Fratta, &c. Ato. Bologna, 



1678. N°4, p. 80. 



This ingenious author, having practised in the most famous mines of Europe, 

 in this short treatise teaches how to make pure metals out of the respective 

 ores. 



ji further Prosecution of Experiments with Phosphorus. By Dr» Frederic Slare, 

 F.R.S. Philos. Collect, N°4,'p.'84.- 



To try the elasticity of this shining substance, when brought to a flame, I 

 made the following experiment. I conveyed a quantity of it into a small bubble 

 of glass, as large as a nutmeg, but blown very thin in the flame of a lamp, that 

 it might be the more sensible to the elasticity of the substance expanding into 

 flame. Then I hermetically sealed up the end of the stem of this glass-bubble, 

 so that no air, nor any thing else, could escape, without breaking it. Then I 

 approached the sealed glass to the warmth of the fire, and soon found it kindle 

 into a flame, and to continue to do so by emitting flames, and as it were filling 

 up the whole capacity of the glass for some short time; after which it seemed 

 to be extinguished without breaking the glass, or so much as cracking it. 



That I might satisfy myself what this matter so flaming did resolve into, I 

 made the following experiment. I made another small bubble, with a large 

 tube for the neck, and left it open at the top to be as a chimney to the fire be- 

 low it in the ball ; then I made the matter flame as before, by approaching it to 

 the heat, and found my chimney as well as the upper part of the bubble lined 

 with a yellowish sulphur, which though thus sublimed was not yet wholly di- 

 vested of its shining property; but when a little warmed the whole bubble 

 shone. 



To try at what rate it would burn in the open air, I made a piece of it flame 

 merely by approaching it to the warmth of the fire, and found it burn like a 

 piece of nitre, but without any explosion, for it only flamed away pretty quick. 

 I have further observed that it leaves a red tenacious matter on its going out, 

 not unlike red wax^ and is so sour that it sets the teeth on edge, and dissolves 

 iron. 



