This is the final part of my look at Paul R Hill's book.
Section 6 takes a look at the sounds associated with UFOs.
"Saucers emit a characteristic noise generally referred to as a hum, buzz or whine...the data quite clearly shows that the forcefield cycles at the hum frequencies." (p119.)
A later section ponders the silent operation of UFOs; and looks back to another of his own observations, in 1962. Then, Hill watched "...a fat aluminium or metallic coloured 'fuselage'...approaching from the rear." The craft accelerated rapidly and was lost in clouds. There was no noise associated with the observation. Hill wondered how it would be possible to have noiseless, supersonic flight?
"First of all, the UFO is such a reliable machine that broken or discarded parts are extremely rare." (p225.)
Looking to explain sightings of the filament style "Angel Hair" Hill concludes: "This line of reasoning suggests that angel hair may be a liquid on board the various UFO types, stored under pressure and released to the atmosphere through small orifices, solidifying when it hits the lower pressure and temperature conditions of the atmosphere." (p244.)
Section 20 concludes "Analysis of the structural properties of UFOs shows that they are some form of craft having weight, mass, solidarity, high density and a hard or tough structural shell." (p311.)
"Being knowledgeable of US Government secrets on propulsion, I have know from the start that UFOs could not possibly be of Earth technology manufacture." (p311.)
The seven appendices of the book are full of technical analysis of aspects of the author's arguments made throughout the work.
This was not an easy book to read, due to the technical nature of much of the material. However, it did give some insight into lines of argument and logic in which Hill engaged, when analysing raw data from actual UFO sightings.
One of the few criticism I have of the work of Hill's interpretations from some of the UFO case data. It seems to me that from the perspective of looking back 40-50 years, that some of his conclusions, rest on shaky case data. If this data is not good, then his line of argument could be incorrect.
However, for anyone of a technical bent, I would recommend you track down a copy of this book and form your own conclusions.