452 PHILOSOPHICAL TRANSACTIONS. [aNNO I7O8. 



mersed, which was about a sixth part less space than wliat the same air possessed 

 before the injection, and still remains so, notwithstanding it is constantly exposed 

 to the open air. Which plainly shows that the springs, or constituent parts of 

 the air, do not in time totally restore themselves after standing so long bent. 

 And had not the heat come on, but the air continued in that state as at first 

 injected for a year or two, I doubt not but its springs would have been rendered 

 much more incapable of restoration. From hence it is easy to conclude, that 

 if nine or ten atmospheres of air were condensed in the space of one, and to 

 remain in that state for a year or two, that when the vessel containing them 

 shall become exposed open to the air, that' then bodies, such as very thin glass 

 bubbles, supposing them not to be above five or six times specifically heavier 

 than their like bulk of common air, would float on such a medium. But I am 

 not sure of this, and do not know but it may be the means of rendering air visible. 



An Experiment y shotving the Production of Light within a Glass Globe, whose 

 inner Surface is lined with Sealing-wax, on an Attrition of its Outride. By Mr. 

 ,,.Tr. Hauksbee, F. R. S. N° 318, p. 2 1 p. 



I took a glass globe, about 6 inches diameter, into which putting a conve- 

 nient quantity of broken sealing-wax, I held it over a moderate fire till the wax 

 was melted, then turning it about from part to part, it soon had got a pretty 

 thick lining to it, on more than half its inside. Thus placing it in a conve- 

 nient position, I left it till it was perfectly cold. After having fixed the brass- 

 work to it, I caused it to be exhausted of its air, then fixing it on the machine, 

 to give it motion as usual, I no sooner held my hand on that part of it where 

 it was lined with the wax, but the figure of the parts that touched it was as 

 visible on the inner surface of the sealing-wax as when the glass alone is used 

 for that purpose. Where the sealing-wax is spread thinnest on the glass, one 

 can but just discern the light of a candle through it in the dark; but some parts 

 are so covered with it, that it is at least one 8th part of an inch in thickness ; 

 and even on those parts, the light and figure appeared as vivid and distinguish- 

 able as any where else. The light produced is not at all discernible through the 

 body of the wax, but only to be seen through the transparent part of the glass ;• 

 and notwithstanding some parts of the sealing-wax did not adhere so closely to 

 the glass as others, yet the light appeared on those parts as on the other. Now 

 whether the light produced on the sealing wax, was from the effluvia caused by 

 the attrition of the surrounding body of glass, or from its own disposition to 

 do so in such a medium, I cannot determine ; it being of the same colour and 

 - likeness to that of glass in all respects, except that, on a small quantity of air 

 being let into the receiver, the light wholly disappeared in that part lined with 



