3870 =H. A. Hazen—Prvjection of Lines of Equal Pressure. 
Only an approximate solution of the problem is claimed ; at 
the same time it is quite satisfactory and if used will open a 
wide field for meteorological research, especially if there be a 
few additional stations established along the 50th and 55th 
parallels. 
An exact determination of elevation of pros is 
tions in the west would be of very great importa 
series of observations, conducted at elevated and fewer preci! 
in the west, for a whole year, as acess by Lieut. Dunwoody 
in the preparation of his tables, would be of great assistance in 
determining a proper formula of Srcduatios to sea-level. 
TABLE VI. 
For reducing pressures, at elevations not exceeding 1000 feet, to sea-level. 
h 
ot — 64 = in 
60158°6 x (1+ 0) * ae + : a De oe 
this 8’ and ¢ refer to the pressure and temperature at the u ve grants h= 
altitude of station. Argument, h, 8 and ¢, 8 = #’ + correction from table. 
Formula: log 8 = log B’ + 
100’. 200’. 
Press’e 29''-4.| Press’e 29''-9.' Press’e 30''-4, Press’e 29''-8./Press’e 29''°8. Press’e 30''*3. 
4a T. 
Cc. | Diff. C Diff. | ¢ Diff. Cc i. Cc Diff.| ¢ | pir. 
. 100’. r 
100’. = | aO0'. 
80°|""102 | *102 | ‘103 | -104| -105 | -105 || 0°) -203 | -102 | -206 | -104 | -210 [ °105 
75 | °103 | °103 | 104 | -105 | -106 | -106 75 | -205 | °103 | -208 | -105 | -212 | “106 
70 05 | 106) -107 | -108 70 | 207 | -104 | -211 | *106 | -214 | “108 
65 | °105 | -105 | -107 | -107 | -108 | -309 5 | -209 | -105 | -213 | “107 | -216 | 109 
06 | 106 | -108 | -108 | -109 | +110 “211 | °106 | -215 | °108 | -219 | “110 
120 | -120 | -122 | -122 | -124 | -124 5 | 239 | -120 | -243 | -122 | -247 | 124 
O | 7121 | +122 | -123 | -1241-125 | -126 0 | 242 | -122 | -246 | -124 | -2 126 
= 123 | 123 | +125 | +125] -127 | -127 5| +2 25 | -253 | °127 
: "132: *13: 
—40 | "134 1-134 | -136 | °137 | -138 | -139 ||— 
: *269 | *1é 2 
*268 | 135 | °272 137 | 277 | 138 
