Hello Peter,
Another aside, if I may, on the use and selection of Quartz. There is
an interesting description in "The Perfect Machine : Building the
Palomar Telescope" about how General Electric hand selected train loads
of Quartz in their failed attempt to manufacture fused quartz mirror
>I wonder if anyone knows how large a spherical crystal ball might be made?
>I have
>used glass spheres as small as 6" diameter for my sundials but prefer
>larger, about 9" diameter.
>Is this size a possibility?
>Can one machine quartz crystal with tools appropriate for glass? Ie.,
>diamond saws,
>Dear fernando,
>
>I don't know too much about the radio side of quartz production, but it was
>needed during the war to make oscillators for the radio industry (and
>military, of course). These plates must be cut at a highly specific angle
>>from a certain part of the crystal. Problem is, that ma
Peter Tandy wrote:
-- I don't know too much about the radio side of quartz production, but
it was
needed during the war to make oscillators for the radio industry (and
military, of course). These plates must be cut at a highly specific angle
from a certain part of the crystal. ... .
Dear fernando,
I don't know too much about the radio side of quartz production, but it was
needed during the war to make oscillators for the radio industry (and
military, of course). These plates must be cut at a highly specific angle
from a certain part of the crystal. Problem is, that many quar
Those interested in sunshine recorders might like to
consult the chapter 'Measurement of the duration of
sunshine and starshine and of the intensity of solar
radiation' in the 'Handbook of Meteorological Instru-
ments Part 1' published by the UK Meteorological
Office
Peter Tandy wrote:
> Dear les, and everyone,
>
> In the Natonal collection of minerals in London, we have a superb QUARTZ
> sphere which should make an excellent sunshine recorder, and such spheres
> are available on the mineral market, mainly for the 'crystal healing'
> brigade. however, being a
Dear les, and everyone,
In the Natonal collection of minerals in London, we have a superb QUARTZ
sphere which should make an excellent sunshine recorder, and such spheres
are available on the mineral market, mainly for the 'crystal healing'
brigade. however, being a natural substance, quartz is o
Message text written by "Les Cowley"
>Old syle fortune tellers peered into crystal balls. Maybe there
is a supplier somewhere of fortune telling accessories!<
Hmmm, presumably they will have 'foreseen' this demand already and no doubt
are writing to us ;-)
Patrick
>I suspect more than a tad too expensive for most of us.
>Besides, where's the fun in buying ready made, when
>one can build it for oneself?
Old syle fortune tellers peered into crystal balls. Maybe there
is a supplier somewhere of fortune telling accessories!
Les Cowley
Patrick Powers reports:
>I sent them a message and got the following reply:
>. Price in UK is £747 and cards are £56 / 200...
>A tad too expensive for me though Patrick
I suspect more than a tad too expensive for most of us.
Besides, where's the fun in b
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