XXVin INTRODUCTION. 



Table 31 gives to hundredths of a grain the vakie of every tenth of a gram 

 from O.I to 9.9, and the value of every gram from i to 99. The vakies of 

 hundredths and thousandths of a gram are added as an aid to interpolation. 



WIND TABLES. 



CONVERSION OF VELOCITIES. 



Table 32. Synoptic conversion of velocities. 



This table,^ contained on a single page, converts miles per hour into meters 

 per second, feet per second and kilometers per hour. The argument, miles per 

 hour, is given for every half unit from o to 78. Tabular values are given to 

 one decimal. For the rapid interconversion of velocities, when extreme pre- 

 cision is not required, this table has proved of marked convenience and utility. 

 Table 33. Conversion of miles per hour into feet per second. 



The argument is given for every unit up to 149 and the tabular values are 

 given to one decimal. 

 Table 34. Conversion of feet per second into miles per hour. 



The argument is given for every unit up to 199 and the tabular values 

 are given to one decimal. 

 Table 35. Conversion of jneters per second into miles per hour. 



The argument is given for every tenth of a meter per second up to 60 

 meters per second, and the tabular values are given to one decimal. 

 Table 36. Conversion of miles per hour into meters per second. 



The argument is given for every unit up to 149, and the tabular values 

 are given to two decimals. 

 Table 37. Conversion of meters per second into kilometers per hour. 



The argument is given for every tenth of a meter per second up to 60 

 meters per second, and the tabular values are given to one decimal. 

 Table 38. Conversion of kilometers per hour into meters per second. 



The argument is given for every unit up to 200, and the tabular values 

 are given to two decimals. 

 Table 39. Scale of velocity equivalents of the so-called Beaufort scale of wind. 



The personal observation of the estimated force of the wind on an arbi- 

 trary scale is a method that belongs to the simplest meteorological records and 

 is widely practiced. Although anemometers are used at meteorological obser- 

 vatories, the majority of observers are still dependent upon estimates based 

 largely upon their ow^n judgment, and so reliable can such estimates be made 

 that for many purposes they abundantly answer the needs of meteorology as 

 well as of climatology. 



A great variety of such arbitrary scales have been adopted by dififerent 

 observers, but the one that has come into the most general use and received 



1 From Hand-Book of Meteorological Tables. By H. A. Hazen. Washington, 1888. 



