ii6 Mayow 



inverted and placed under the orifice of the other 

 glass, and raised in it in the following manner. 

 A transverse rod has to be attached, from the first, to 

 the inner sides of the glass, as is seen in Plate V., 

 Fig. 4. And let a string be so suspended from the 

 rod that both its ends, drawn from under the ori- 

 fice of the glass, hang outside. Then one end of 

 the string is to be tied to the bottom of the glass that 

 is to be raised, and the other end pulled till the glass 

 rises above the surface of the water inside. When the 

 water has fallen out of the glass which has thus been 

 pulled up in an inverted position, and air has taken its 

 place, let this glass be pulled down by means of an- 

 other string previously fastened to its mouth, and taken 

 out of the other glass^ in such a way that its mouth 

 may remain continuously inverted ; and then, lastly, 

 the air contained in it may be transferred to the glass 

 first described, in the manner already shown. 



Although air generated from the aforesaid fermen- 

 tation possesses no less elastic force than common air, 

 it does not on that account follow that it is really air 

 — viz., such as possesses vital and igneous particles. 

 For that air in which an animal or a light has expired 

 possesses elastic force in an equal degree with inviolate 

 air, and yet it is destitute of nitro-aerial and vital 

 particles. But in order to determine whether this air 

 generated anew is fit for sustaining life or not, let the 

 following experiment be performed. But before this 

 can be done, it is first of all necessary that air of that 

 sort be generated in suflBcient abundance, which can 

 be done as follows without any great waste of the 

 aforesaid liquid. Let a sufficiently large glass be im- 

 mersed in water and filled with it, and let it remain 

 inverted. And now let the air generated in a small 

 glass, in the manner described, be transferred to this 



