VOL. XXVI.] rHILOSOPHICAL TRANSACTIONS. 520 



this experiment with a quantity of common sulphur, nearly equal to what I had 

 used before of the flowers ; which having melted as before, I poured it into an- 

 other globe-glass, which I used in all respects as the former. But when I had 

 exhausted it, and given the usual motion and attrition, the effect was so sur- 

 prisingly different, that one would scarcely think it could proceed from the same 

 sort of matter. For the figure of my hand and fingers appeared not only on 

 its inside, (though more faint and pale than in the experiments of sealing-wax 

 and pitch) but on its outside there appeared a brisk purple light, very beautiful 

 to the eye. The strength of this light may be judged from hence, that the 

 lines of the palm of my hand, being near the touching parts, were easily dis- 

 coverable by it. And as this common sulphur differed vastly, in that part of the 

 experiment already related, from the former, so likev/ise in the latter ; for when 

 the ring of threads was held over it, (under the same circumstances as in the 

 other) they were directed towards it as vigorously as in any experiment hereto- 

 fore made. The parts lined and transparent performed much alike : if there 

 was any difference, it seemed to incline to that part lined with the sulphur. In 

 this experiment also, as in the last, the sulphur was loosened, and separated 

 from the glass that contained it : which therefore cannot be urged, as anywise 

 conducing to the unsuccessfulness of the former. 



I repeated this last experiment with a large quantity of sulphur, and I poured 

 about two pounds of it melted into a glass globe of the same size as the former, 

 being about 5 inches diameter ; this, when cold, contracted itself, and became 

 loose from every part of the glass, as in the former experiments. The sulphur 

 covered more than half the inner surface of the globe, and its thinnest part was 

 about half an inch in thickness ; towards the axis it appeared to be more than a 

 full inch thick. This glass, when exhausted of its air, was used in every re- 

 spect as the former. The light produced on its outside was very considerable, 

 and attended with the same colour and vivacity as before ; nor was that less 

 vigorous on its inside. Comparing it with the former, notwithstanding the 

 thickness of the lining, it was at least 4 times greater; but the figure of the 

 fingers was not now so distinguishable, as in the other. But on the part near 

 the axis, where the substance of the sulphur was much the greatest, no light 

 was produced ; which may be attributed in a great measure to the slowness of 

 the motion, and the weakness of it there, in comparison with that which is 

 made more remote from it, where it was that the light was seen within. What 

 farther is observable was, that the light, visible on its outside only, appeared to 

 be produced between the inward surface of the glass and the convex surface of 

 the sulphur ; the sulphur being loose from it, gave liberty for the air to be 

 taken from thence, as well as from the other parts : the light which was there 



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