272 NOVUM ORGANUM 



We hear that some sort of boat or vessel has now been 

 invented, capable of carrying men some distance under 

 water. Any bodies, however, can easily be suspended 

 under some such vessel as we have mentioned, which has 

 occasioned our remarks upon the experiment. 



Another advantage of the careful and hermetical closing 

 of bodies is this not only the admission of external air is 

 prevented (of which we have treated), but the spirit of 

 bodies also is prevented from making its escape, which 

 is an internal operation. For any one operating on natural 

 bodies must be certain as to their quantity, and that noth 

 ing has evaporated or escaped, since profound alterations 

 take place in bodies, when art prevents the loss or escape 

 of any portion, while nature prevents their annihilation. 

 With regard to this circumstance, a false idea has prevailed 

 (which if true would make us despair of preserving quan 

 tity without diminution), namely, that the spirit of bodies, 

 and air when rarefied by a great degree of heat, cannot be 

 so kept in by being inclosed in any vessel as not to escape 

 by the small pores. Men are led into this idea by the com 

 mon experiments of a cup inverted over water, with a candle 

 or piece of lighted paper in it, by which the water is drawn 

 up, and of those cups which, when heated, draw up the 

 flesh. For they think that in each experiment the rarefied 

 air escapes, and that its quantity is therefore diminished, 

 by which means the water or flesh rises by the motion of 

 connection. This is, however, most incorrect. For the air 

 is not diminished in quantity, but contracted in dimen 

 sions, 91 nor does this motion of the rising of the water 



91 Part of the air is expanded and escapes, and part is consumed by th 

 flame. When condensed, therefore, by the cold application, it cannot offer suf- 



