Arizona republican., 1915-02-21

the stands shown in the cut. The boards of which the roof is made are $ inches thick by 3-4 inches wide. They overlap each other enough and
 are placed at such an angle as to exclude direct sunlight and rain while they are separated by an inch in the | clear to allow perfect ventilation. The l floor is of the same material and as ! it's purpose is to intercept radiation l from the earth it should be wide
 enough to reach from edge to edge 1 of the roof. The shelter is exposed with the long side of the roof to the southward while to facilitate reading
 the lower section of the other side
 which. since it faces away from the
 sun, is made shorter. is hinged. The
 extension of the floor was left to
 receive a pan of water if it was
 thought desirable to note the freez-
 ing point. The stand is of d height
 to carry the instruments about three
 feet above ground.
 1 It has not been thought necessary 1 to give exact measurements as ther-
 mOmeters are of different sizes and
 are mounted in various ways. If the
 main objects to be attained are kept | in mind: namely. shelter from sun.
 rain and radiation: simplicity and
 cheapness of construction: and DOT
 tability; a similar and equally effec-
 tive shelter should be easy to build
 from this description and the append i ed photograph.
 Note-The following are verbatim
 excerpts from paragraphs GA and 65
 of 'Meteorology." text book on the
 Weather, the causes of it's changes
 and weather forecasting for the stu
 dent and general reader. By Willis
 lsbister Milham, Ph. D.. field mem
 orial professor of astronomy in Will Hams College:
 l "64. The Real Air Temperature-A ] thermometer exposed in the open air
 gives neither during the day nor at
 night the real air temperature, even | if it as an accurate, standard in strument During the day it will in dlcate temperature anywhere from ! 20 to 60 degrees above the real air temperature, because the excess of the insOlation received over the ra-
 diant energy emitted is large. During i the night the thermometer may indi-
 cate ;t temperature from one to se- ven daerees below the real air tenn perature. because it is radiating more l heat to the sky and earth than it is receiving. close approximation to 1 the real air temperature can he de-
 termined in summer by exposing the ! thermometer in the shade of small
 tree, and in winter by placing it on | the inside of q north piazza post [ The indications of the instrument in these positions will give approximate i ly the real air temperature, although they may differ in certain cases hy as much as three or four degrees In meteorological work the real air temperature is determined in one of three ways; namely, by means of a ] thermometer shelter sling thermome-
 ter. or ventilated thermometer
 60. Theremometer Shelter - The 1 thermometer shelter as used by the ! United States weather bureau con i sists of cubical box about three feet on a side, with a double sloping
 roof, closed bottom. and latticed
 sides. The purpose of q double roof
 is to shield the thermometers from the insOlation of the sun. The outer portion of the roof absorbs the inso- 1 lation, and the circulation of air be- tween the two portions If the roof prevents the lower layer from becom- | ing heated. The tight bottom eX- | cludes rising air currents and inter-
 cepts any radations from the earth. i while tue latticed sides allow a free circulation of the air. The shelter must be located at least five feet above the ground. It has been found 1 as q result of many experiments that the indication Of the thermometer in
 such q shelter usually gives the real air temperature correct to within half q degree. It is most in error on still. i clear, cold nights, and on still. hot
 summer days In both cases the in
 ~