272 PHILOSOPHICAL TRANSACTIONS. [aNNO 1675-(J. 



presses the bronchia of the arteria aspera, that it expels the air out of them, and 

 presses their sides together. But it appears not probable that the blood of the 

 vena arteriosa can thus compress those bronchia, being inclosed in its vessels, 

 which hinder it from compressing others. And the bronchia being harder than 

 the arterial vein, they will compress it more easily than be compressed by it. 

 It is therefore far more probable, that if the lungs be compresed that compres- 

 sion be made by the pleura, which may be swelled within the breast, as the skin 

 is swelled without. 



But it is not necessary that the lungs be compressed in vacuo, to make them 

 subside in water. For we have often put pieces of lungs and whole lungs in 

 the vacuum, and they remained there extremely swelled; but as soon as the air 

 was again admitted, they became very flat and red, and sunk to the bottom in 

 water. Which shows, that it is sufficient for getting the air out of the lungs, 

 to render them close and red : and we have not been able to produce this ef- 

 fect but by means of the exhausting engine. For we have left lungs a whole 

 night between two plates, with a great weight upon them, to endeavour to ex- 

 press the air out of them, but without success ; and those lungs still floated on 

 the water. We have also tried to make the air re-enter into the lungs after 

 they were rendered solid in the engine, which was very easy ; for drawing them 

 out from the bottom of the water, and blowing into the aspera arteria, the 

 lungs swelled again, and resumed their ordinary colour, and floated on the 

 water. And this is what happens to the lungs of infants newly born. 



Promiscuous Experiments with the Air-pump. By M, Huygens and M, Papin. 



N° 122, p. 544. 



Putting a covered receiver, a fourth part of which was filled with water, over 

 the flame of a candle, the water boiled very quickly, yet the glass not much 

 heated, so that the water boiled near a quarter of an hour with a great ebulli- 

 tion, and the glass was no more than tepid. After it was removed away from 

 the flame, the water continued a great while boiling, and began again from 

 time to time. On making the same experiment with a gauge, all the bubbles 

 that issued out of the water did not make the mercury rise sensibly. After- 

 wards exposing this receiver to the frost, the ice which was formed in it was not 

 quite free from bubbles, though the water had boiled in the vacuum, which, 

 one would think, should have driven out all the air: yet the bubbles were there 

 far less numerous than in ice made of ordinary water. The quicksilver was not 

 much raised in the gauge. Afterwards this ice was melted, and the water 

 abroad put to freeze again, still without taking it out of the vacuum, and this 

 second time it was much freer from bubbles. 



