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John Lahr's homemade shake table. This is an interesting
device to watch, as it demonstrates the effect of quake frequencys (rpm
of the hand drill motor) on several items that can be placed atop the platform.
The 4 white strips item to the right was very dramatic in response to the
frequency of the quake (drill); the lower the frequency the more the tallest
white strip vibrated, and the higher the frequency the drill ran, one could
see the various smaller strips begin to oscillate in resonse.
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Edward Cranswicks poster of California Public Seismic
Stations. This is one of many throughout the building. Edward
was a co-host of this meeting, and has been a long time supporter of amateur
seismology; the same as John Lahr.
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One of the many John Lahr exhibition items. I never
had much of a chance to inspect it, but it appears to simulate the effect
of a magnet and coil...induction, with other circuitry.
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Another John Lahr exhibition item. This item shows
the effect of the earths magnetic field.
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Another John Lahr exhibition item
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Another John Lahr exhibition item. The green and
white rectangular item is a magnetic viewer (i.e.; magnetic viewing film).
It is a sandwich of clear plastic, which has millions of tiny magnetic
flakes suspended in clear oil. The device can be used to the magnetic
patterns on magnetic items. When used for normal magnets, the pattern
around magnet edges and between poles shows up as a white area. When
used on an item like a 4 pole magnet (one piece), it will clearly show
the division lines between the poles.