( 581 ) 
I alfo wiiht for fame of thf Glow worms', with which I formerly 
made other Trials, For though I forgot nor, what operation the 
withdrawing of the Air, by our Eng fas is wont to have upon li- 
ving creatures, yet that made me not forbear my wifti * not only 
becaufe 6f the different effed I have found the Engine to hive on 
Infetfs in rcfped of other Animals, but becaufe I am not of the 
opinion of thofe modern Writers, who will have the Light of 
Glow worms depend altogether upon their Life, and end with it. 
But being not likely by my wifhes to procure sny new fubjed to 
make trials on, I thought fitatleaft to do what was in' my power? 
and accordingly (to gratifie them, who, I prefumed, would, if 
prefenc, propofe fuch a Trial) eaufed a piece of iron to be forged, 
whofe top was ofthebignefs of a Nutmegs the reft being aftemm, 
of an inch, or an inch and a half long, for which we provided a 
little Candkftick of Tobacco-pipe-chy, which would not yield 
any fm oik to fill and darken th $ Receiver, Then having heated 
the Iron red-hot, and placed it in this Clay, fo that the round pare 
was clearly protuberant, we conveyed it into a Receiver of white 
Glafs, which wis fo placed as to keep the fides at as good a di- 
ftance, as we could, from the Iron , leaft the exceftive heat fhould 
fas we much feared it would) break the Glafs, Then fending a- 
way the Candles, and making the Room dark,we haftily pumped 
out the Air, but could not perceive the withdrawing of it had any 
operation on the glowing Iron. And the ugh it continued fhining 
long enough to give us opportunity to pump out.and let in the 
Air three teverai times, yet we could nor obferve, that the ^?ir 
had any manifeft operation one way or other. For though upon 
the withdrawing of the Air the Iron grew dimmer and dimmer, 
yetthat I attributed to the cooling of it : and the rather, btcaufe, 
having (to examine the conjedure) let in two or three times the 
Air, when the Receiver had been exhaufted, there appeared no 
manifeft iacreafe of Light upon the fudden admiftion of it. 
Experiment VIII. 
I T Aving formerly in our Rhyfico-Mechdnichall Experiments a- 
jj bout the Spring of the ^/Vobferved, That the Air is thus 
far a Vehicle ol Sound, that a Body but faintly founding, being 
placed 
