deg..99 |
|---------------|---------------|---------------|---------------|
|Mean 48 deg..505|Mean 47 deg..925|Mean 48 deg..169|Mean 49 deg..15 |
+---------------------------------------------------------------+

The tables of Dr. Hildreth, from 1826 to 1854, inclusive, furnish,
generally, evidence of a like character. There are, however, an anomaly or
two which will be observed. From 1826 to 1830, the mean is high during
the period when spots were at a maximum. But that maximum embraced a much
less number of spots than the two succeeding ones. A contrast appears in
the tables of Dr. Hildreth, during the early period, for Dr. Holyoke's
register, for 1827, puts it _below the mean_, but Dr. Hildreth's one of
the _highest of the half century_. In 1835 commenced a period when the
spots were much more numerous, and from 1835 to 1838, inclusive, the
seasons were correspondingly below the mean. From that period to 1844 a
gradual and slightly irregular rise took place, excepting the year 1843,
when another cold year intervened. The table of earthquakes, published by
the British Association, closes with 1842, and I have not access to any
others. The occurrence of such cold years, in the warm period, at
intervals during the two centuries previous, and in 1812, and onward, and
evidently owing to increased volcanic action beneath the western portion
of the northern hemisphere, justifies the belief that the low temperature
of 1843 was owing to the same cause. The following are the means from the
tables of Dr. Hildreth:

+----------------------------------------------------------------+
|1826 54 deg..00|1831 50 deg..87|1836 50 deg..03|1841 52 deg..18|1846 53 deg..64|
|1827 54 deg..92|1832 52 deg..42|1837 51 deg..57|1842 52 deg..83|1847 52 deg..00|
|1828 55 deg..22|1833 54 deg..56|1838 50 deg..62|1843 50 deg..77|1848 52 deg..50|
|1829 52 deg..38|1834 52 deg..40|1839 52 deg..54|1844 53 deg..25|1849 52 deg..09|
|1830 54 deg..93|1835 50 deg..65|1840 52 deg..35|1845 52 deg..73|1850 51 deg..48|
|------------|------------|------------|------------|------------|
|Mean 54 deg..29|Mean 52 deg..18|Mean 51 deg..52|Mean 52 deg..35|Mean 52 deg..32|
+----------------------------------------------------------------+

The observations of Dr. Holyoke were made at Salem, Massachusetts; those
of Dr. Hildreth at Marietta, Ohio.

The following, in relation to the freezing of the Ohio Rive