Brown knew particles were smaller than pollen.
Wilkinson
David M
DM
D000538:Aluminum Silicates / Q000737:chemistry*; D000077215:Clay; D049672:History, 19th Century; D009038:Motion; D010316:Particle Size; D011058:Pollen / Q000033:anatomy & histology*; D014867:Water
D000538:Aluminum Silicates; D014867:Water; D000077215:Clay