1865] WRITINGS OF JOSEPH HENRY. 447 



is attainable in astronomy, will probably ever transcend the 

 sagacity of the wisest, even when assisted by the highest 

 mathematical analysis. But although such precision cannot 

 be looked for, approximations may still be obtained of great 

 importance in their practical bearing on the every-day busi- 

 ness of life. 



The greater part of all the observations which have been 

 recorded until within a few yenTs past has been without 

 system or co-ordination. It is true that the peculiar climate 

 of a given place may be determined by a long series of 

 isolated observations, but such observations, however long 

 continued, or industriously and accurately made, can give 

 no adequate idea of the climate of a wide region, of the 

 progress of atmospheric changes, nor can they furnish an 

 approximation to the general laws of the recurrence of phe- 

 nomena. For this purpose a system of observation must 

 be established over widely extended regions within which 

 simultaneous records are made and periodically transmitted 

 to a central position, where by proper reduction and discus- 

 sion, such general conclusions may be reached as the mate- 

 rials are capable of yielding. 



In discussing the records, the empirical method does not 

 suffice. It is necessary that a priori assumptions should be 

 provisionally adopted, not however at random, but chosen 

 in strict accordance with well-established physical principles, 

 and that these be finally adopted, rejected, or modified, as 

 they are found to agree or disagree with the records. It is 

 only by this method that the different causes which co-operate 

 in the production of a series of complex phenomena can be 

 discovered, as is illustrated in the history of astronomy, 

 which previous to the investigations of Kepler consisted of 

 an unintelligible mass of records of observations. But even 

 with the application of the best possible process of discussion 

 the labor necessary to be expended on such large masses of 

 figures, in order to deduce simple results, is far beyond any 

 individual effort, and can only be properly accomplished by 

 governmental aid. 



The importance of a combined system of meteorological 



