Condign volumes 1 to 3

Read from the scan by GLM-OCR; expect the odd misread word.

# UNCLASSIFIED

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appears between what are taken to be highly charged 'balls' seen as sources of coloured or white light, usually at the extremities, forming a triangle, cone or rectangle.

6. Gas Absorption The absorption spectra of gases at ordinary pressures show narrow dark lines, although it is possible to find regions of continuous absorption. After an atom or molecule has taken up energy from light it may collide with another particle and an average increase in the velocity of particles may occur. Each atom energised can only exist for $ 1 0^{-7} $ to $ 1 0^{-8} $ sec. and unless a collision occurs the energy will be emitted as radiation. At low pressures the time between collisions is long, hence the gas becomes a source of radiation and there is not true absorption. The re-emitted light often has the same wavelength (resonance radiation). Under some circumstances the re-emitted light may have a longer wavelength than the incident light. This is known as fluorescence. In either resonance or fluorescence some of the light will be removed and dark lines would be seen in an examination of the spectral response.

7. Aerosol Fluorescence If it is postulated that some UAP comprise clouds of aerosol particles, then it is necessary, briefly, to examine fluorescence from solids. According to Stoke's Law the wavelength of the fluorescent light is always longer than that of the absorbed light. In the UAP context it seems unlikely that (if fluorescence is indeed the mechanism of making an aerosol cloud appear as a visible mass) this could be caused by radiation of the particles by any radar system. The source radiation must be shorter in wavelength than visible light, leading to the postulation that the cause

may be IR or UV bursts from a natural source.

8. Scattering Intensity The scattered intensity is proportional to the incident intensity and to the square of the volume of the scattering particle and on wavelength. Hence, if an aerosol cloud exists (say at high altitude) and is radiated with a light source, the reflected light seen by an observer will be critically dependent on particle size. Long waves would be expected to be less effectively scattered than short ones because the particles themselves present obstructions to the waves, which are smaller (compared with the wavelength) for long waves than for short ones. The intensity viewed is proportional to $ 1 / \lambda^{4} $ As red light $ \lambda= 7 2 0 0 $ has a wavelength 1.8 times as great as violet light $ \lambda=4 0 0 0 $ the law predicts $ (1.8)^{4} $ or ten times greater scattering for the violet light from particles much smaller than the wavelength of either colour. Hence, if white light is scattered from sufficiently fine particles the scattered light always has a bluish colour. If the size of the particles is larger, then the scattered light becomes whiter.

9. Pollution In passing it is suggested that the reported increase in atmospheric pollution (particularly over large cities) may have a bearing on the charged aerosol phenomena (reported at Working Paper No.19) and thereby the increasing incidence of UAP reports. That there is a clear connection with the particles in suspension in earthquake and volcanic zones is reported elsewhere in the report.

## SONOLUMINESCENCE

10. Sonoluminescence is the production of wide-spectrum light, visible by the human eye, due to the compression of gas