20 EEPORT OF THE SECRETARY. 



Reference was made in the last report to the " Instructions for research 

 relative to the ethnology and philology of America," prepared in 18G1 

 by Dr. George Gibbs, and the fact was stated that a new edition of this 

 work had been undertaken in behalf of the Institution by Professor 

 Powell. During the year 1877, a volume entitled "Introduction to the 

 Study of Indian Languages " has been printed, and a few copies dis- 

 tributed among those interested in the study of Indian languages for 

 such additions and emendations as may be suggested preparatory to 

 final publication. In its preparation Professor Powell was assisted by 

 Prof. W. D. Whitney, the distinguished philologist. 



METEOROLOGY. 



The Institution during the past year has continued its labors in the 

 line of the reduction of meteorological observations. It has been espe- 

 cially engaged in the discussion of material for a new edition of the Rain- 

 fall Tables for North America. It has also reduced and printed the ob- 

 servations made by Professor Caswell at Providence, from the termina- 

 tion of his series of meteorological observations published in 1860 down 

 to the close of 1876, the whole making a continuous series for a period of 

 forty-five years. Long series of this kind are of great importance in de- 

 termining any change of climate which may have occurred during the 

 period which they embrace. 



We mention in regard to this series an interesting fact in connection 

 with the supposed change in the rain-fall in different parts of the United 

 States due to the clearing off of forests. If, for example, we take from 

 this series three ten-year periods, one at the beginning, one at the middle, 

 and one at the end, we observe a regular increase instead of diminution 

 in the amount of rain fall in Providence, as shown by the following- 

 figures: 



From 1832 to 1811, average 3S inches. 



From 1852 to 1861, average 44 inches. 



From 1867 to 1876, average 49 inches. 



This fact, however, may be in some way connected with the custom 

 is-nich, I am told, has become common in New England since the inhab- 

 itants have devoted themselves largely to manufactures, of allowing a 

 considerable portion of the soil which was formerly under cultivation to 

 grow up in wood. 



The next series of observations which remains to complete the results 

 t>f the whole meteorological system of the Smithsonian Institution will 

 be that on the pressure of the atmosphere, which is intimately con- 

 nected with the dominant winds in different parts of the country. 



The miscellaneous work by the meteorological computers of the Insti- 

 tution during the year 1877, is as follows: 



1. Tabulating the mean temperature and the maxima and minima of 

 temperature for the Smithsonian stations for the years 1871-'72-'73. 



2. Tabulating rain-fall, temperature, and maxima and minima for 

 Canadian stations, 1875. 



