VOL. v.] PHILOSOPHICAL TRANSACTIONS. 507 



looking upon them again some time before I was to go to bed, about 10 liours 

 after they were first included, they seemed to be quite dead, and though the air 

 was forthwith restored to them, they continued to appear so, till I went to 

 bed ; yet I thought fit to try, whether time might not at length recover them, 

 and leaving them all night in the receiver, I found the next day, that three if 

 not four of them were perfectly alive. 



Exp. II. — We took from a hedge a branch, that had a large cobweb of ca- 

 terpillars in it, and having divided it into two parts, we put them into like re- 

 ceivers, and in one of them shut up the caterpillars together with the air, 

 which from the other was exhausted. The event was, that in that which had 

 the air, the small and scarcely visible insects, after a short time, appeared to 

 move up and down as before, and so continued to do for a day or two ; after 

 which, other occasions made the experiment to be neglected ; whereas that 

 glass whence the air had been drawn out and continued kept out, showed after 

 a very little while no motion that we could perceive. But to try whether cater- 

 pillars may continue so far alive in our vacuum all the winter, as, the next 

 spring or summer, to proceed in the transmigration to a butterfly, is a trial 

 that we have but begun, and therefore must not pretend to say any thing about 

 its event. 



The Nineteenth Title. 

 Of the Phcenomena suggested hy JVinged Insects in our Facuum. 



When our physico-mechanical experiments were dispatched to the press, 

 the inconvenient season of the year, and the difficulty of making the receivers 

 I then employed to keep out the air for any long time, hindered me from then 

 publishing above a trial or two of what would happen to winged insects in our 

 vacuum. But afterwards being provided with more commodious vessels, I 

 thought fit at several times to repair that omission by various attempts, the 

 chief of which are as follow. 



Exp. I. — Nov. 12, about eight o'clock at night. There were taken four 

 middle sized flesh flies, which having their heads cut off were inclosed in a 

 portable receiver, furnished with a pretty large pipe and a bubble at the end. 

 As soon as the receiver was exhausted, those flies lost their motion (which 

 was not brisk before ;) an hour or two after, I placed them near the fire, which 

 restored not their motion to them ; wherefore I let in the air upon them, after 

 which in a very short time they began one after another to move their legs, 

 and one or two of them to walk ; and having kept them all night in a wann 

 place, when I sent a person the next morning to try, if they would manifest 



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