TABLE VI. Extreme monthly range of temperature at New Heven, Williamstown, Brunswick and Williamsburgh, for the year 1827, with the average monthly range at Brunswick for g years, from 1820 to 1827 inclusive, and at Brunswick and Williamsburgh, respectively, for three years, 1820, 1826 and 1827. MONTHS. 1827. 52.0 62.5 54.5 52.0 62.3 57.7 63.2 50.5 46.8 51.7 51.3 40.2 36.3 36.3 33.3 August 43.0 46.8 46.0 43.0 40.5 38.3 37.7 If we would estimate the average temperature of the State from the data afforded by the preceding tables, it may be observed, that the Latitude of Brunswick being nearly at the central point of the extreme latitudes of the sea coast, and the position of the College, where the observations were made, some miles from the sea, the temperature observed there may be considered as very nearly representing the general mean temperature of the whole extent of the country bordering on the sea coast. The position of Williamsburgh being near the centre of the State, observations made there might be thought to serve as a fair indication of the average of the whole, but probably this would require some corrections. The elevation of the place of observation at Williamsburgh, is about 1627 feet above the level of the sea, and is estimated to be about 400 feet higher than the general level of the surrounding country, and about 700 feet higher than the average level of the habitable part of the surface lying in the same parallel across the State (exclusive of the mountain summits in the counties of Somerset and Oxford.) From a comparison of observations made by scientific men, on the decrement of mean, heat in departing from the equator, or in ascending vertically from the level of the sea, it appears that the mean heat in departing from the equator diminishes from 1°. to 1° 45 of Farenheit for every degree of latitude, and the diminution in ascending is found to vary from 1° for every 210 feet to 1° for every 300 feet perpendicular elevation.* In this State the ratio of 1° temperature to 1° latitude, or to 300 feet elevation may be assumed as probably nearest the truth. Taking these principles as the basis of correction, it would give 42° 9 as the mean temperature of the country about Williamsburgh, and 43°. 8 as the mean of the same parallel across the centre of the State.-The observed means at Williamsburgh will be found in the tables. As a farther correction, and to assist future investigation, it may be observed, that the mean temperature of the interior of the earth, at some depth below the surface, is doubtless very near, and probably exactly, that of the mean temperature of the atmosphere at the surface in the same latitudes; and as the temperature at considerable depths is more uniform, and less liable to sudden changes from transient causes, more dependence can be placed on the results of such observations, where they can be obtained, for instance at the bottom of deep wells, or in permanent springs on the surface, which are shaded from the sun. Dr. Williams found the temperature of the water of a well 45 feet deep, in Rutland, Vermont, to be uniformly exactly that of the annual mean temperature of the atmosphere; and the temperature of other wells of different depths, and at different places in New-England, to approximate so nearly to the supposed mean temperature of those places, as strongly to V *See Humboldt's personal narrative of travels in South America. p. 262, and Edinburgh Encyclopedia, Article Meteorology p. 172, and Article Physical Geography p. 586. Hist. Vermont, p. 43. corroborate the argument. The writer of the article on meteorology in the Edinburgh Encyclopedia, in a course of observations in the year 1813, on the water of a well 25 feet deep, found that the temperature of the water varied very little at different seasons, the extremes differing only 5 deg. 9 min.; and the mean differing only four tenths of a degree from the observed mean between the extremes of temperature of the atmosphere for the same year. The temperature of a well 25 feet deep in Williamsburgh, situated at the same level where the observations of the temperature of the atmosphere were made, near the summit of a high hill, and supplied, not by springs flowing from higher grounds, but by the water with which the earth at that depth appears to be saturated, is found in August, September and October, to be 46 1-2 degrees, which is a few degrees higher than the observed annual mean of the atmosphere; but as the observations have not been continued through the year, the variations of the interior heat at different seasons are not known. So far however as can be inferred from this experiment, and from the theory stated above, it would seem, that the observations for the annual mean temperature at Williamsburgh, were made in a manner to give a result rather below than above the true mean. The observations at different places given in the preceding tables being made simultaneously, they will as far as they extend, exhibit a fair comparison of the climate of Maine with that of the other places to which they relate. Observations also made at different places in different years, will afford a proximate comparison, which often may be very near the truth, and not usually very far from it. For this purpose the following table of the mean temperature of several places, distant from each other, on this continent, is extracted from Williams's History of Vermont, p. 47. And to assist and extend the comparison, the mean of the summer and winter months respectively, is added in a form to correspond with the division of seasons in the preceding tables. A farther view of the climate of Maine may be obtained by a comparison with that of England, as exhibited by an abstract from the journal of Dr. Burney, given in table eight. TABLE VIII. Meteorological observations at the Royal observatory, Gosport, Eng. Lat. 50° 47′ N. Long. 1° 7′ W. for the year 1826. Dr. Burney remarks, that the mean temperature of 1826, was 1 deg. 42 hun. above the mean of the preceding 10 years. The mean temperature of Brunswick, it will be observed, (see table IV.) was also in the same year, 1 deg. 80 min. and that of Portland, 2 deg. above the mean of 8 years; and that of Williamsburgh, half a degree above that of 3 years. To facilitate a comparison of the whole, some of the principal results of the preceding tables are exhibited at one view in |