Box 17, Folder 9: Meteorology (Milwaukee) 1859-1871

January in the coldest month and July the warmest; January shows the greatest range of temperature; July the least.

[Sketched and then penned in line graph of mean monthly temperatures]

Projecting a curve of mean monthly temperature it will show not a regular arch gradually rising to the summit and then falling with the same regularity but the ascending curve in the first half of the year will be found concave while the descending curve in the last half of the year will be found to be convex; indicating an abnormal depression of temperature in the early part of the year and an equally abnormal excess in the autumn months.

[Handwritten statistics of all the data from observations]

This table, which has been compiled with great care from MSS. in my possession, will be found valuable, by enabling us to compare the climate of Milwaukee with that of other places. It will be seen that the general mean temperature deduced from all the observations in 46.018; that the coldest year was 1856 (41.057) differing 8.037 from the warmest year, 1845 (49.094); the coldest month is January (22.076) though in six cases February was the coldest. January 1857 was the coldest month known since the first settlement of the place (7 3/4º)

July is the warmest month (70.021); July in 1854 being the warmest month observed. In 1848 June was the warmest month; and in 1861 & 1863 August was the warmest.

The winter and spring of 1845 were the mildest of the 18 years; the winter of 1856, and the spring of 1857 were the coldest .The hottest summer, 1854, was followed by the mildest autumn.

It will be noticed that no extreme of temperature either of heat or cold, [has] indicated in the table by block figures, has occurred since 1857. If we take the mean annual temperature of five years together, it will be found that the term ending with 1848 was much the warmest (48.048); the terms ending in 1853 (46.071) and in 1863 (46.036) were near[ly] the general mean; while the intermediate term ending with 1857 was the coldest (42.056).

[In there remarks reference is had to the general results of all the observations for a month, or year, and not to particular days; thus although the thermometer was lower in January 1864 than in the same month in 1865, the mean result as about the same in both.]

thus indicating that there may be truth in the popular theory of "cold terms" or "warm terms" of year.

B. Printed Circular-Meteorological Tidal Observations.

[List-This sheet sent to the following persons, handwritten].

From the Milwaukee Sentinel, March 7th.

Meteorological and Tidal Observations,

Made under the direction of Capt. Geo. G. Meade, Topographical Engineers, Superintendent Survey of the N. and N. Western Lakes, at Milwaukee, Wisconsin; Lat. 43° 03' N., Long. 87° 56' W.; Height above the Sea, 593 feet; above Lake Michigan, 15 feet; FOR THE MONTH OF FEBRUARY, 1861, BY I. A. LAPHAM

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