rig^ 



Br &iitkriey 



I'dioJiv 



Syphon Form. 



*Column of Glycerine, 48" = Mercury 



„ Mercury 



Value of Column in inches of Mercury 



3" 



28" 



31 



Now, suppose an extreme fall of three inches of mercury represented by 

 the fall of the two fluids in this barometer ; of this the diminution of the 

 glycerine column will be -if of ^ of the whole barometric fall ; the alteration 

 of the levels of the two surfaces of mercury will be each one half of the 

 remainder. 



Diminution op 'Column. 

 \% of 16" of Glycerine = 15" = Mercury ... -9375 



l^ij Mercury + l^ij Mercury 2"-0625 



FaU 3"-0 



Value of Resulting Column. 



33" Glycerine = Mercury 2"-0625 



Mercury Column, 28" - 2^V" = 25"-9375 



28"-0000 



Total Resulting Column. 

 = 58"-9375 



* Hypothetical specific gravities, following Dr. Guthrie's example. 



