[ i6 + ] 

 time ; fo that the longer the inter- 

 val between rilling it with air and 

 pufhing in the Aider is, the more 

 the infide of this tube is cleared 

 from water, and thus the more air 

 it will contain. This error may alfo 

 amount to three fub-divifions. 



VI. The fixth error, which may 

 be committed by the fmall tube or 

 meafure, is indeed remedied in the 

 meafure in - ufe by our author by 

 the flat Aider; but it remains in 

 the meafure which is ftill ufed by 

 other philofophers, which confifts 

 only in a common phial not pro- 

 vided with fuch a Aider. The er- 

 ror refulting from the want of this 

 Aider may amount to ten, and even 

 more fub-divifions. 



VII. The feventh error may de- 

 pend upon the difference in the di- 

 ameter of the fmall meafure com- 

 pared 



