Show Why Thermometers s I lary ry Thermometers vary Yary In their Indica Indica- Indications Indications lions mainly on account rif f exposure assuming that the Instruments themselves them selves register similarly under like conditions The height above ground is an un important important factor particularly on still nights wh when n radiation lion Is quite active near the earths earth's surface at which time important differences between between be be- tween thermometers thermometers located only short distances apart are nrc record recorded ell When there Is considerable air nil movement these differences disappear to a great extent |