506 PHILOSOPHICAL TRANSACTIONS. [aNNO 16QI , 



Of this solid I have had some parcels much more vigorous and inflammable 

 than others. When I made some experiments last summer with this solid 

 phosphorus, every one handled it without any danger: but I have since had 

 some parcels that would scarcely endure the touch of a warm hand, without 

 taking fire and burning. Making some experiments in the company of a very 

 worthy and ingenious gentleman, I laid down a piece of this luminous substance, 

 about two drachms in weight, and it took fire when no candle was in the room ; 

 it blazed like a faggot, and burnt the carpet and board it lay upon : this sort is 

 only for the experienced and careful to meddle with. The less vigorous af- 

 forded us this experiment. We wrote with a pointed end what words we pleased 

 in the light ; then we removed into the dark, and had very radiant and legible 

 characters, looking like words written with a beam of light. If we carry these 

 glorious letters to the fire side, and suffer them there to grow warm, they will 

 presently turn into dark lines, and remain as long as good ink may be thought 

 to do. This light is very diffusive of itself, for I have marked down above a 

 hundred characters with this illustrious pencil, and found not a twentieth part 

 consumed. In like manner I weighed oat half a grain, and spread it over my 

 hand at night, which it gilded all over and continued light all the night ; for so 

 I found it next morning. As a further proof of its diffusive quality, having 

 weighed out one grain and counterpoised it in good scales, it continued to 

 flame in the open air for seven or eight days, insomuch that shutting my study 

 windows by days, I could always see a beam of fire, and when I looked intent 

 upon it, it sent up a white flame into the ambient air; which a large piece does 

 very remarkably. After all was burnt out, we had no ashes or recrements, save 

 only a little moisture which tasted subacid. Having suffered a larger piece to 

 burn out, I had more moisture, which tasted like a weaker oleum sulphuris per 

 campanain.* Its fumes are sulphureous; and in all its properties it seems mostly 

 referable to sulphurs on account of its inflammability, and because it neither 

 loses nor is dissolved in water. 



What medical use may be made of this noble concrete, time may discover. 

 And what service it may be of in helping us to explain other phsenomena of 

 nature, I should be glad to know, particularly as to that observation of the 

 learned Dr. Croone, who, on rubbing his body with a fresh and well warmed shift, 

 has made both to shine; and also that of a worthy Bristol gentleman, who with 

 his son told me, that after much walking, both their stockings will frequently 

 shinc-f* 



• Phosphoric acid. (Phosphorous acid of the new nomenclature.) 

 f An electrical phenomenon. 



