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Eudiometer, is a new word; it 

 Signifies an inftrument by which we 

 may judge of the degree of falu- 

 brity of the common air. The in- 

 vention of fuch an inftrument be- 

 longs to Dr. Prieitley. It confifts 

 chiefly of a glafs tube, divided in 

 equal parts; for inilance, in two 

 large divisions ; each of which is 

 divided into ten others, and each of 

 thefe ten fub-divided again into ten. 

 parts : and a glafs meafure, contain- 

 ing exactly one of the great divifions 

 of the tube. One meafure of com- 

 mon air and one of nitrous air, put 

 together in a feparate glafs vefTel, 

 and left by themfelves till the dimi- 

 nution of the bulk of the two airs is 

 compleated, and afterwards let up 

 in the glafs tube, indicates at once 

 the exact: diminution of the two 

 joint meafures. The degree of 

 6 goodnefs 



