PHENOMENA OF THE UNIVERSE. 141 



was to be placed ; then I placed above that another plate 

 metallic and not wooden, that could stand of itself at the 

 bottom of the vessel. B ut if that body be small in size, 

 when it is received into the hollow of the plate, it forces the 

 air together, and does not expel it ; but if of greater magni 

 tude than to admit of the easy yielding of the air, the air 

 impatient of this greater pressure, somewhat lifts up the 

 plate, and ascends in bubbles. 



And I had a hollow leaden globe made, the sides of it 

 sufficiently firm to bear the force of a mallet or of a press : 

 and this globe, being struck at either pole with mallets, 

 approached nearer and nearer to a planisphere. And it 

 yielded more readily under the first contusions, afterward 

 less so, according to the measure of the condensation; so 

 that at the last the mallets were of but little service, and 

 there was need of pressing, and that with some violence. 

 But I enjoined, that, after the pressing, a few days should 

 be suffered to elapse, but this has no relation to our present 

 design, but looks another way. 



Air, by a powerful exsuction into closed vessels, is ex 

 tended or dilated, so that part of the air being removed, the 

 remainder nevertheless fills the same measure as the whole 

 had filled ; and yet so as to endeavour, as much as possible, 

 to restore itself and to get rid of that extension. You may 

 perceive this in eggs, which contain scented water, and are 

 broken in play, so that they imbue the air with their scent. 

 The way to try it is to let all the food that is in the egg be 

 drained, then let a person confine, by a powerful exsuction, 

 the air itself which has found its way in, and immediately 

 on exsuction bore a hole with the finger, place the egg thus 

 closed under the water, and then take away your finger. 

 But the air turned aside by this tension, and endeavouring 

 to recover its place, draws the water, and enters till that 

 portion of air regains its former consistency. 



I have tried the same experiment with a glass (or philoso 

 pher s) egg, and find that the water received is about an 

 eighth part of the capacity ; so much was the air extended 

 by exsuction. But this depends upon the greater or less 

 violence of the exsuction. But toward the end of the exsuc 

 tion, it drew with it the brim of the vessel itself. I moreover 

 made use of a new experiment, namely, after exsuction to stop 

 up the hole with wax, and let the egg remain so sealed up for 

 a whole day. I did this to try whether that day would lessen 

 the inclination of the air, as is the case in consistent bodies, 

 in twigs, bars of iron, and the like, the motions of which, 

 to recover themselves from tension, become feebler through 



