Show COUNT THE DUST PARTICLES scientists of united states depart ment of agriculture are invest bating gating the atmosphere in connection with the solar radia radle tion work of the weather bureau united states department of agrical ture a dally daily count Is being made of the number of dust particles in the at mos pher at washington to make the count the air lessure lyes sure within the dust counter Is suddenly decreased causing a line of dust to be precipe bated on glass where the particles are counted with a microscope having a magnification n of 1000 diameters on quiet mornings as many as 3 dust particles per cubic centimeter ha have v been counted but on ea elear ear mornings morning following precipitation the number drops to most of the particles appear to be extremely fine minerals or organic matter from the earth a surface al though some unconsumed carbon from smoke gypsum and calcite from build ing operations and diatomaceous ma ina aerial have been observed undoubted doubted Cn ly there are many particles which while large enough to act as nuclei for condensation are too email small to mojie be seen I 1 through a microscope with a magnify ing power of 1000 diameters |