APPENDIX C LXXXV 
Anemometer Comparison: The anemometer in use at Canadian 
stations has never been compared with those in use in other countries; 
it is designed on the assumption that the distance travelled by the 
wind is three times the distance travelled by the centre of the anemo- 
meter cups in the same time. This factor has been found to be too 
high in other countries, and for the standard anemometer at Kew, 
the factor 2-2 instead of 3 has been found to be correct. The Dines 
pressure tube anemometer has been very carefully compared on a 
whirling machine and with the Kew standard; for this reason a pres- 
sure tube anemometer was erected on the same tower as the Canadian 
cup anemometer four years ago, and the records given by the two 
instruments have been compared. The mean of all velocities gives 
the cup anemometer readings higher than those of the Pressure Tube 
but the factor is variable and intermediate between 2-2 and 3. 
Electric Potential of the Air: The self recording electrometer for 
measuring the potential of the air has been in operation throughout 
the year, and the results to date will be published shortly. 
Evaporation: Observations on evaporation have been made at 
the Central Office for some years, and during the past two years the 
observations have been continued during the winter by weighing 
a pan of water or ice, and from the loss in weight from day to day, 
the amount of evaporation has been calculated. Owing to the in- 
creasing requests for evaporation data, it is proposed to extend the 
observations this year and establish evaporation stations at about 
seven places in the Dominion. 
Earth Temperature: Mr. Patterson has designed a special commu- 
tator for use with resistance thermometers by means of which it will 
be possible to get continuous records of earth temperatures at various 
depths on one instrument, and it is hoped to get it installed during the 
year. 
Barograph and Thermograph: The barograph and thermograph : 
obtained for recording the pressure and temperature on the top of 
Sulphur Mountain at Banff has been overhauled in the office, and they 
will now work for about a month without requiring attention. Mr. 
Patterson has substituted a mercurial barometer for the aneriod 
on the barograph and by means of a float arranged to compensate 
for temperature changes, he has converted the barograph into a 
compensated mercurial barograph recording at a distant station. 
AGRICULTURAL METEOROLOGY 
At the General Assembly of the International Institute of Agri- 
culture held in Rome in May, 1913, it was unanimously resolved that 
the subject of Agricultural Meteorology, should become a recognised 
