195 



[23] 



edge of the mean temperature of a considerable number of stations, many 

 of them remote from the more populous parts of the United States. It 

 should, however, be remembered that the instruments provided never ex- 

 ceeded a thermometer and a rain-gauge ; and the observations, therefore 

 had of necessity a limited range. ' 



In 1825, a similar system of observations was introduced into the State 

 of New York, almost without modification. Each of the academies incor- 

 porated by the Board of Regents was furnished with a thermometer and a 

 rain-gauge, and was required to keep a register, affer a prescribed form, in 

 order to be entitled to a portion of the pubhc literary fund. Tliis system 

 has novy continued hv more than twenty years, and tbe nmnber of 

 academies reporting has increased from ten to forty. The plan was highly 

 creditable to the public spirit and scientific taste of New York. It was a 

 movement in advance of pubhc sentiment in the other States, and the ob- 

 servations were, perhaps, as extensive as it was expedient to undertake at 

 that time. These observations have determined, with considerable accu- 

 racy, the mean temperature of the State; and the annual report contains 

 a vast amount of important meteorological statistics. 



More recently, Pennsylvania has set an example of the same kind to her 

 sister States. In 183T the legislature of that State appropriated .§4,000 for 

 the advancement of meteorology; and out of this sum, which was placed 

 at the disposal of a joint committee of the American Philosophical Society 

 and Franklin Institute, a barometer, two common thermometers, a self- 

 registering thermometer, and a rain-gauge, were purchased for each county 

 in the State, to be placed in the hands of some skilful observer who 

 should volunteer to keep a journal of the weather, according to a com- 

 mon form prescribed by the committee. The observations were com- 

 menced with little delay, and have been regularly continued. Here are 

 made observations of the barometer and thermometer three times a day; of 

 the self-registering thermometer; the winds estimated for sixteen points of 

 the compass; the depth of rain; and, at some stations, observations of the 

 dew-point. 



In the year 1843, the system of observations at the military posts was 

 reorganized upon a scale more in accordance with the claims ot science. 

 They now comprise observations of the barometer, attachf^d and external 

 thermometer, wet-bulb thermometer; direction and force of the wind; di- 

 rection, velocity, and amount of clouds; each at four hours of the day, 

 viz: sunrise, 9 a. m., 3 and 9 p. m.; together Avith the amount of rain, 

 and the times of its beginning and ending. 



Thus it appears we have observations from the general government at 

 about sixty posts, stretching along the entire Atlantic coast, the gulf of 

 Mexico, the Indian territory beyond the Mississippi, and the chain of 

 the northern lakes. Next come the observations of two large States, 

 New York and Pennsylvania. And then we have amateur observers, 

 pretty numerous in New England — scattered more sparingly over the south 

 and west. 



I now come to the inquiry, what progress has been made, 



2, Towards deducing from these observations general laws. 



In the list of philosophers who have contributed to create science out of 

 the crude materials furnished by observation, I shall first mention Mr. 

 Redfield. His first paper on the storms of the Atlantic coast appeared in 

 April, 1831; in volume 20 of the American Journal of Science. This 



