268 Meteorological Register for 1823-4-5, kept at the 



in some measure be accounted for from the circumstance, that 

 the facts are few and the period of observation remote ; while 

 the changes, if any, have been exceedingly slow, and their ratio 

 to the alleged causes exceedingly uncertain. 



" The United States, however, appear to offer an opportu- 

 nity of bringing the question to the test of experiment and ob- 

 servation. For here within the memory of many now living, 

 the face of whole districts of country has been entirely chang- 

 ed ; and in several of the States two centuries have effected 

 as much as two thousand years in many parts of Europe. In 

 this respect, the ' Landing of the Pilgrims' in 1620 is as re- 

 mote a period as that of the' invasion of Gaul or of Britain by 

 Julius Caesar. 



" The time for improving this opportunity, however, like 

 that for recording the history, language, manners, and customs 

 of the aborigines of the country, is fast passing away ; and in a 

 few generations, both these sons of the forest and the intermi- 

 nable wilderness they inhabited will, for all useful purposes, 

 be as though they had never been. As, therefore, the military 

 posts within the United States afford every convenience for 

 making numerous observations over an extensive district of 

 country, and regular diaries of the weather have for some 

 years past been kept at most of them, the following tables have 

 been prepared in the form that appears best calculated for re- 

 ference, in order to preserve the facts thus collected. 



" The first twelve tables for each year give the mean of the 

 observations at the several posts for each month, and the thir- 

 teenth the mean for the whole year. The last, or general 

 table, gives the average of all the observations at the several 

 stations, and also the average for the several years, calculated 

 in the manner hereafter stated. Should it be practicable to 

 obtain similar observations for eight or ten years, it is proposed 

 to collect, if possible, such as may have been made at an early 

 period after the settlement of the country, in order to ascertain 

 what changes, if any, have taken place, either in the mean 

 temperature, the range of the thermometer, the course of the 

 winds, or the weather in the Atlantic States. 



" The posts at which these observations were made are situ- 

 ated between 9.T bT and 46^39' of north latitude, and be- 



