The adhering states of soils on the fiber surface were observed with optical and electron microscopes. The amount of large soil particles of diameter above 10 μ on the soiled cloth was comparatively less. From the electron micrographs it was observed that a number of small flat particles having the diameter less than 1 μ which can not be detected by the optical microscope, adhere on the fiber surface.
The spectroscopic analysis of inorganic soils gave the spectra of Si, Al, Ca, Mg, and Fe as the strongest lines and the intensities of other lines were very weak. The electron and X-ray diffraction were also experimented for the composition of the inorganic soils.
The analyses of the organic soils extracted from naturally soiled cloths were carried out by IRR spectroscopy, gas chromatography, thin-layer chromatograpy (TLC) and gel filtration. The existence of triglycerides, cholesterol and its ester and hydrocarbons such as paraffin and squalene in organic soil was identified by TLC. In the gel filtration, two peaks were found in elution diagrams of the detergent solution after washing naturally soiled cloths.