THE INFLUENCE OF LEAD IODIDE AEROSOL DISPERSITY ON ITS ICE-FORMING ACTIVITY

Lead iodide aerosol ice-forming activity obtained by thermocondensation in a cloud chamber has been studied. Lead iodide aerosols have been found to yield a maximum number of 2 x 10(18) kg-1 of ice crystals at 253 K. At 263 K the maximum output amounts to 3 x 10(16) kg-1 and at 268 K lead iodide aerosols are generally inert. Ice-forming characteristics of the lead iodide are inferior to those of silver iodide and copper acetylacetonate, but are better than those of phloroglucinol and copper sulphide. The possibility of producing ice-forming nuclei with 10-fold reduced lead iodide content is considered by coating inert nuclei with small quantities of active substance. The activity of such coated nuclei is estimated.