how thefe Effluvia of Glafs be’come capable to ASt or Per- 
form the Office of a Solid Body, or why fuch a Medium 
is requir’d in the inward Glafs to produce the Light, I 
think are worthy the Confiderarion of this Society. For 
I have try’d, that upon letting in a little Air, the Ap- 
pearance of it dy’d, nor ceuld it then be recover’d in that 
ftate altho’ diligently endeavour’d. 
V. An Account of an Experiment made before the Royal 
Society at Grefliam College, May 28. 1707. 
' Touching the 'Difficulty of Separating two Hernia 
fpheres , upon the injecting of an Atmofphere of Air 
on their outward Surfaces , without withdrawing the 
included Air. By Mr. Fr. Hauksbee, P. S. 
S ince the greateft Satisfa&ion and Demonftration that 
can be given for the Credit of any Hypothefis, is, 
That the Experiments made to prove the fame, agree 
with it in all Refpefts, without force : As in that of 
Sound, the Air is prov’d the proper Vehicle to communi- 
cate it, not only by its lefiening according to the degrees 
of Rarifa&ion 5 but by its increafing according to the 
Degrees of Condenfation. Now altho the Preffure of the 
Air is evident by a number of Undeniable Experiments 
made by the Air Pump $ Yet the feveral Phenomena of 
which, being liable to be accounted for by the Suffionijls, 
and Funiciilarians, to proceed from fome (unintelligible) 
Internal Caufe $ therefore to put the Matter of Faft (I 
think) paft all Difpute, I devis’d tjie following Experi- 
ment. 
14 Y 2 l 
