REPORT OF THE SECRETARY. 25 



tliree inontlis, when notbiug will remaiu to be doue but tbc maps and 

 some general deductions. 



To defray tbe cost of the labor iu the preparation of tUis work otber 

 tbau tbat of Professor CofBn himself, an appropriation has been made 

 from the income of tbe Institution. Tbe world will not only therefore 

 be indebted to the Institution for the publication of the work, but also 

 for the collection of tbe material and a part of the expense of tbe reduc- 

 tions. 



I may mention tbat tbe previous publication by the Institution of the 

 Winds of North America has been largely made use of by the English 

 Board of Trade iu constructing their wind-charts of the northern oceans, 

 and tbat the work now in process of prejiaration will be of especial value 

 for a similar purpose. 



The temperature observations are still in progress of reduction, two 

 compntors being engaged upon the work. The progress of their labors 

 has, however, frequently been interrupted by calls from diflerent por- 

 tions of the country for reports on the climate of different districts. 



The following is an account of the present condition of this part of 

 the general reductions : 



The collection and tabulation, in tbe form of monthly and annual* 

 means, of all accessible observations of the atmospheric temperature of 

 the American continent and adjacent islands, have been completed to 

 tbe close of the year 1870, and extensive tables representing the daily 

 extremes, or the maximum and the minimum at the regular observing 

 hours, have been prepared. 



An exhaustive discussion of all tbe observations available for tbe 

 investigation of the daily fluctuations of the temperature has been 

 made, and this part of tbe work is now ready for tbe printer. 



Tbe discussion of the annual fluctuations of tbe temperature has 

 been commenced and carried as for as the present state of other parts 

 of the discussion would permit. 



The construction of a consolidated table giving the mean results, 

 from a series of years, for each month, season, and the year, at all of 

 the stations, which will probably exceed 2,500 in number, has been 

 begun and comj)leted for that part of the continent lying north of tbe 

 United States, and also for several of the States. This is perhaps tbe 

 most laborious, as it is one of tbe most important parts of tbe dis- 

 cussion. In many of tbe large cities there are numerous series, made 

 by various observers, at different hours, all of which have to be brought 

 together, corrected for daily variation, and combined to obtain the 

 final mean. To give some adequate idea of the time and labor involved 

 in the preparation of these tables, it may be mentioned that, in tbe State 

 of New York alone, there are about three hundred series, which are 

 derived from nearly two million individual observations. 



The principal sources from which tbe general collection of results 

 has been derived, may be enumer^ited as follows: 



