At 20:34 8/19/99 -0600, Anthony L. Mourkas wrote:
>I accept the decision but am still unclear as to the scientific
>explanation as to why it is the difference in column heights rather than
>the height difference in one column.  If anyone could educate me further
>my enquiring mind would like to know.

Couple of ways to imagine here that may help.  First, suppose that all the
water was magically in one arm of the tube, held up by a miracle.  If you
add 11" of pressure to the bottom of the water, it will go up 11".  Well,
it's really the same thing in the folded tube.  The top of the water is 11"
above the bottom of the water, and it takes 11" of pressure to do it.

Second way -- instead of the U-tube you have gone to Bangor and laid
another dam across the Penobscot 500 yards above the existing one, and
covered the whole thing over with magically rigid plastic.  You poke two
holes in the plastic, one of them takes a long tube that sits in the
water.  Drive your propane truck up to the other and hook up a regulator
into the hole.  Turn on the gas and go have lunch (in Augusta <g>).  When
you get back, the river will have gone down (say) one micron and the level
in the tube will have risen 11" minus one micron -- bringing it to 11"
precisely above the (new) water level.

Does that help?
david
David Beierl - Providence, RI
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"