On Sal Nitrum and Nitro- Aerial Spirit 97 



clearly opposite effects seem to be produced from the 

 same cause. Nor was any error committed in making 

 the experiment, for when often repeated the result 

 was always the same. 



But now to submit our views in explanation of the 

 phenomenon, it is in the first place probable I say that 

 not only the air which was contained in that part of 

 the glass in which the water rose after the first action, 

 but that nearly all the air in the glass was impaired 

 by the first action. For we notice that in about two 

 hours after the said action the water had risen so as to 

 occupy a fourth part of the glass more or less. But it 

 is not to be supposed that in that space of time the 

 exhalations or vapours produced by the action were 

 entirely condensed. Nay, they will never entirely 

 become liquid, as will be shown below. Let us 

 suppose then that this exhalation is contracted to the 

 extent of a half by condensation (for I have ascertained 

 in a way to be described below that exhalations of that 

 kind will only condense to the extent of about a half 

 in so short a time as that in which the water rose in 

 the glass), and it follows that the space in the glass, 

 including that into which the water did not rise, is 

 about half occupied by exhalations not yet contracted ; 

 since this has undergone a contraction equal to half 

 the space which is left in the glass before the water 

 could rise in it. 



And in this a reason must be sought for the water 

 not rising, after the action set up the second time, 

 above the mark from which it was depressed. No 

 doubt the effervescing particles which issued from the 

 previous action being mixed in great profusion with 

 the aerial particles, impaired them in the way to 

 be described below ; and the water in consequence 

 rose into the space which was left not only by the 



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