150 BULLETIN 1059, U. S. DEPARTMENT OF AGRICULTURE. 
For all stations the dial reading should be recorded in the field at 
each observation, and the dial readings and total movements should 
be tabulated in adjacent columns of the "Humidity, Wind, and 
Evaporation" form. The decade means or sums and the monthly 
sums and means should be computed and entered. For most uses 
the decade sums will be preferable to means. The record of day and 
night movements may be obtained either from two dial readings 
per day, or from hourly automatic records. 
Where hourly records are available, the greatest wind movement 
for any single hour of each day should be entered, and also the total 
wind movement by day and by night; that is, from 6 a. m. to 6 p. m., 
and from 6 p. m. to 6 a. m. This division of the daily movement is 
of interest in the general study of the climate, and may assist, for 
example, in determining relative amounts of evaporation during the 
day and night, when this is not readily determined directly. 
The monthly, annual, and growing season means of the movements 
obtained from dial readings, and of maximum hourly velocities, and 
the sums of day and night movements obtained from automatic 
records, with the mean hourly movements computed therefrom, may 
be tabulated on the " Summary " form. 
Instruments. 
Self-registering Instruments : 
Single register complete (for wind velocity), with a year's supply 
blank Forms 1015, pen and ink (by special arrangement a reg- 
ister to carry wind record for one week may be obtained) $95.00 
Two magnet registers- 
No. 2, for wind velocity and sunshine (using Form No. 
1015-C) 125. 00 
No. 3, for wind velocity and rainfall (using Form No. 
1015-D) 130. 00 
No. 4, for wind velocity, rainfall, and sunshine (using Form 
No. 1015-E) 140. 00 
Quadruple register complete (for wind direction, wind velocity, 
rainfall, and sunshine), with a year's supply of blank Forms 
1017, pens and ink 275.00 
In all of the above, cable and battery for electrical installation 
are extra. 
Anemometers, wind vanes, and supports : 
Anemometer, Robinson's; of the standard pattern, complete with 
aluminum cups and wrench; all dimensions and construction to 
be identical and small parts interchangeable with corresponding 
parts of the anemometer of the Weather Bureau 52. 00 
Anemometer cups, aluminum, witb arms, G. S. S. No. 12200; per 
set 8.00 
Anemometer cups, copper, reinforced, .013 inch thick, hemmed at 
edges and arms reinforced, G. S. S. No. 12201; per set 9.50 
Wind vane ; small, for towers, witb mounting, complete, G. S. S. 
No. 12274 13, 50 
