8 E.. Loomis— Contributions to Meteorology. 
that these cases of low pressure on Mt. Washington were gen- 
erally the result of great storms in progress, and in most of the 
cases the violence of the storm had ceased at the lower stations 
while it continued unabated on Mt. Washington. The Danish 
Washington are reduced to sea-level by the table on page 4, the 
results will rarely differ one-tenth of an inch from actual obser- 
vations made near sea-level. Exceptional cases will sometimes 
occur; but great anomalies are confined to the colder months 
of the year, and seldom occur except during the progress of 
violent storms. 
In order to ascertain whether the law respecting the reduc: 
tion of barometric observations to sea-level, which has been dis- 
covered for Mt. Washington, holds true for other mountains, 1 
made a comparison of the observations on Pike’s Peak, when 
reduced to the altitude of Denver. © The altitude of Pike’s Peak, 
as determined by a preliminary computation which differs 
slightly from the final result given on page 18 is 14,056 feet, 
and that of Denver is 5,262 feet. The materials employed for 
this comparison consisted of the tri-daily observations from 
November, 1878, to January, 1875, and from January, 1877, to 
July, 1877 (22 months), and the monthly means from November, 
1873, to June, 1879, published in the annuai reports of the Sig- 
nal Service. These materials were reduced in the manner 
already described in the case of Mt. Washington. The table 
on 9 shows the reduction from Pike’s Peak to Denver 
ma ed f 
Tables based on the formula of Laplace (Guyot’s Met. Tables, 
