SECTION I. 



TABLES, DISTRIBUTION, AND VARIATIONS OF THE ATMOSPHERIC 

 TEMPERATURE IN THE UNITED STATES, 



AND SOME ADJACENT PARTS OF AMERICA. 



GENERAL REMARKS. 



The laws of the distribution of winds, rain, and heat of a large portion of North 

 America, embracing the normal or statical values as well as their variations with 

 seasons and for longer periods of years, form part of those studies with whose results 

 we are most directly concerned. Although this ground has been gone over many 

 times and must continue to be cultivated, the continued accumulation of new 

 materials enables the investigator gradually to present his results in a more precise 

 form and to enter more fully into detail or local discussions. Whatever imperfec- 

 tions the available records may possess, their effect in the mean values will con- 

 stantly diminish with the increase of reliable modern observations; moreover, they 

 could not be dispensed with on account of inaccuracies, since they form the only 

 material in our possession for the discussion of such subjects as possible changes in 

 climate since the first settlement of the States. In the following work we shall 

 therefore be chiefly occupied with the establishment of tabular results comparable 

 among themselves, with obtaining mean or normal values or the so-called constants 

 of temperature, as factors of the climate, and with the range of the fluctuations, 

 daily, annual, and secular, also with the generalization of the results either in 

 analytical or graphical form. 



The advantages gained by an early discussion of observations beyond putting us 

 in possession of results for immediate use are several; light is thrown on the 

 reliability of the records, their sufficiency or insufficiency for our present or future 

 wants, and the kind of results they are or are not capable of yielding, is 

 indicated. Besides improvements in methods of observing and in instrumental 

 means are likely to result, as Avell as incitements of the observer to renewed efforts. 



Our earliest records of temperature, the results of which are given in the follow- 

 ing tables, date about a quarter of a century after the invention of Fahrenheit's 

 thermometer,^ and with few exceptions all the observers in this country have made 



The following information is extracted from Gehler's Physikalisches •Worterbuch, Leipzig, 1839. 

 * * To Daniel G. Fahrenheit, of Dantzic (Prussia), is clue the merit of having constructed, 



( vii ) 



