boiling point of water with elevation

Boiling point of water as a function of altitude/elevation/pressure?

From: http://www.hi-tm.com/Documents/Calib-boil.html

TABLE  1	Changes in Standard Temperature and Pressure (in Hg) as a Function of Altitude	(Ref. 1)		TABLE  2	Boiling Point as a Function of Barometric Pressure	(Ref. 2)
Altitude (ft.)	Pressure(in. Hg)	Boiling pt.(° F)		Pressure(in. Hg)	Boiling pt. (° F)	Boiling pt.[added or reduced](° F)
-500	30.466	212.9		27.6	208.04	-3.96
0	29.921	212.0		27.8	208.39	-3.61
500	29.384	211.1		28.0	208.75	-3.25
1000	28.855	210.2		28.2	209.10	-2.90
2000	27.821	208.4		28.4	209.44	-2.56
2500	27.315	207.5		28.6	209.79	-2.21
3000	26.817	206.6		28.8	210.13	-1.87
3500	26.326	205.7		29.0	210.47	-1.53
4000	25.842	204.8		29.2	210.81	-1.19
4500	25.365	203.9		29.4	211.15	-0.85
5000	24.896	203.0		29.6	211.48	-0.52
5500	24.434	202.0		29.8	211.81	-0.19
6000	23.978	201.1		29.921	212.00	0.00
6500	23.530	200.2		30.0	212.14	0.14
7000	23.088	199.3		30.2	212.46	0.46
7500	22.653	198.3		30.4	212.79	0.79
8000	22.225	197.4		30.6	213.11	1.11
8500	21.803	196.4		30.8	213.43	1.43
9000	21.388	195.5		31.0	213.75	1.75
9500	20.979	194.6		31.2	214.07	2.07
10000	20.577	193.6		31.4	214.38	2.38

 

Why?

From: http://www.newton.dep.anl.gov/askasci/phy00/phy00252.htm

Pressure in atmospheres, follow the relation:  p = e^(-ay)  where:
 p is pressure [in atm]
a is 1.16*10^-4 [m^-1] and 
y  is altitude [in m]   
From my chemistry text, log (Po/P) = (deltaH/W)((1/T)-(1/373)) where:
Po is sea level pressure (atmospheres), 
P is pressure, deltaH is  40,700 J/mol, 
W 19.15 [this is a constant of proportionality from the  linearization of a Vapor pressure (atm) vs Temperature  graph.  
Specifically, log p = (-deltaH/19.15*T) + C], T is boiling point  desired and 373 is boiling point of water at one atmosphere.