1847.] Meteorological Observations on Grey Lock Mountain. 207 



River; " so, in the present instance, the lowest station, in defiance 

 of the law, gives the lowest temperature; that is, comparing the 

 Hopper with Grey Lock. Comparing the results at Grey Lock, 

 however, wiih those at the Astronomical Observatory, we have a 

 somewhat near approximation to what the law has been con- 

 ceived to be. I give the mean of the three stations. The obser- 

 vations were taken part of the time, hourly, day, and night, part 

 of the time once in two hours. 



Mean temperature of the week at the Observatory, . 75,116 



Hopper, . . 69.556 

 Grey Lock. . 70.678 

 Allowing Grey Lock to be 2,850 feet above the Observatory, 

 we should have a diminution of one degree in about 645 feet. 

 But this is considerably less than the diminution has been com- 

 monly estimated. Gay Lussac, and Biot, in their celebrated 

 ajronantic expedition, found the diminution to be one degree Centi- 

 grade, for 174 metres or 570 feet, which would give one degree 

 Fahrenheit for 317 feet nearly; showing a diminution twice as 

 rapid as in our experiments. Had the theriuometers at Grey 

 Lock been suspended in the woods near the Observatory there, 

 instead upon the shady side of the building, a very little removed 

 from the building itself, probably its position would have corres- 

 ponded better with that of our standard thermometer at the Astro- 

 nomical Observatory, which was hung in rather a cool situation, 

 north of the latter building, which is of stone. The apparent 

 anomaly presented by the observation in the Hopper and on the 

 mountain, I account for froiu the peculiar conformation of the 

 place. Those who have visited this grand feature in our natural 

 scenery, are aware that the bottom of the Hopper corresponds, in 

 some measure, to the bottom of a well. Vast mountain masses 

 are piled on all sides but one. These, in raid-summer, would 

 naturally reduce the mean temperature. A different result would 

 doubtless be obtained at mid-winter, or even at this season. We 

 propose to prosecute this subject with a view to obtain data for 

 some general formula which shall express the law of diminution 

 sought. 



Our observers took the liberty to extend their observations be- 

 yond the department of Meteorology, and made a somewhat com- 

 plete botanical survey of the mountain. They were rewarded 

 with some new plants, and have received from Chadbourne a fine 

 specimen of the Luzula melanocarpa, a grass which has been sup- 

 posed to be confined to the White Hills, (in New England,) but 

 which he found near the top of Grey Lock, and determined to be 

 the above species. Perhaps this communication is not quite rele- 

 vant to the purposes of your Journal; you can make any disposi- 

 tion of it you please. A. Hopkins. 



