E. Loomis—Contributions to Meteorology. 7 
these cases the observed reduction was greater than that com- 
puted from the Laplace formula. There 1s not a single instance 
in which the observed reduction was 0°3 inch less than that 
computed from the Laplace formula. 
The mean of the numbers in column Sth is 0°362 inch, and the 
mean of the numbers in column 9th is 07190 inch, showing that 
when the reduction is computed from the table on page 4, the 
average error is but little more than half as great as when com- 
puted from the Laplace formula. There are ten cases, out of 
3,285 observations, in which the error of the reduction by the 
Laplace formula exceeds 0°4 inch, and there are only three 
cases in which the error of the reduction by the table page 4, 
ae 0:3 inch. This table is therefore a great improvemen nt 
pon Laplace and also upon any other table of reductions hith- 
seis published. 
these cases enumerated on page 6 occurred during the 
progress of storms which were generally of considerable vio- 
ence. In every case, the barometric minimum on ash- 
ington occurred later ‘than it did near the level of the sea, the 
average retardation amounting to more than eleven hours. In 
most of the cases the barometer at the lower stations had pene 
the minimum, and in about half of the cases had risen to thirty 
inches, while the barometer on Mt. Washington had risen com- 
paratively. little. In a large part of the cases the temperature 
was unusually low and the wind on Mt. Washington was very 
high. In two cases the temperature at Burlington was lower 
than it was on Mt. ee and in other cases the differ- 
ence of temperature was very small. In 18738, Jan. 29.1, the 
thermometer at Burlington was 9° lower than on Mt. Washi ing- 
ton; on Feb. 10.1, it was 2° lower; in 1872, Dec. 24.3, the 
temperature at both stations was the same ; and in 1873, March 
24.1, it was only 2° colder on Mt. Washington than at Burling- 
ton. These observations help to explain in a few of the cases, 
why there was an increased pressure at the lower stations which 
did not extend to the summit of Mt. Washington. A cold 
stratum of air whose height was less than 6,000 feet, flowed 
along the surface of the earth, increasing the barometric pres- 
sure at the lower stations, but producing no Searereey effect upon 
the pressure at the summit of Mt. Was on. 
It will also be observed that in half a ete — the wind 
on Mt. Washington was from the northwest; and in four-fifths 
of the cases it was either west or northwest. The velocity of 
the wind was also remarkable, the average being sixty-six miles 
per hour, and in four instances the velocity was one hundred 
miles or more. In 1875, from Jan. 14th to 17th, the velocity 
of the wind was not reported, but it is presumed to have been 
about one hundred miles per hour. It is evident, dlientstorel 
