Keeping a balance.
Every now and then, we get a little worried about the
contents of the B.B. Sometimes it is
because nobody seems to be writing any articles of a serious nature: at other
times it may be because there has been no climbing or archaeological news for
some time, and so on.
The B.B. should, ideally, have something in it to interest
every club member. Obviously, this
cannot occur in every issue as there is not enough space for a diversity of
articles, even if the Editor had a supply of them to use - which he certainly
hasn't!
However, if such a supply of articles was possessed by the
editor, some attempt would be made to avoid a preponderance of any one type,
unless a definite preference was expressed by a sufficient number of readers.
All of which is leading up to the fact that a lot more
articles of a scientific nature type are on the way. This, we think, will please most
members. Others, whose tastes do not run
in his direction, are invited to rectify the situation by sending in other
types of article. If this occurs, we may
even reach a stage of being able to select the best of what is submitted for
publication.
Alfie
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If you haven't paid your sub this year, and have been sent
this B.B., it is only because your name has not yet been removed from the
list. DON' T LET THIS HAPPEN TO YOU!!!!
Book Review
By Jim Giles,
Shepton Mallet Caving
Club Journal Series 1 Number 3
In this third journal of the
present series, the Rhodamine B water tracing technique devised by members of
the Bradford Pothole Club is discussed by B.M. Ellis. He explains the intricacies of using this
revolutionary spelaeo - aid and describes at length the results of experiments
in St, Cuthbert's Swallet and Swildons Hole. The author makes an interesting comparison between this and other water
tracing methods and concludes with an outline of further applications on
Mendip.
Archaeological Note
As most members will be aware, the field north of the Belfry
is the site of a Roman settlement, presumably connected with lead mining. Excavations were carried out there some years
ago under the direction of Ted Mason and work is now in progress on the
preparation of a report which will be published as a B.E.C. paper. Much pottery has been recovered from this field
since the excavation from ploughed soil and from the drainage trenches which
from time to time are cut across the lower slopes. If any member gets a chance to check the
field again, and finds any pottery or other small find, I would be interested
to see it.
Keith S. Gardner -
Archaeological Secretary
Luminescence
by M. Luckwill
A recent article in the B.B. No. 170, noted the fact that
the stal in Balch's Hole was phosphorescent. This article is intended to provide a simple explanation of the physics
of the phenomenon in order that the reader will be familiar with the terms used
in future articles which will doubtless appear.
For those who have never seen phosphorescence, a short
description of what happens will not be out of place. A flash bulb is fired
close to the stal and when the light from the bulb has died down, the stal can
be seen to glow a bright apple green for a few seconds. Several people are investigating substances
which show this phenomenon, using ultra violet light as a means of
illumination. The process of light
emission during and after illumination is known as Luminescence.
For practical considerations, Luminescence is divided into
fluorescence and phosphorescence. Figure
1 shows the amount of light emitted in relation to time......
Figure 1.
The portion AB represents light emitted during the
illumination and together with any light emitted for 10 seconds after
illumination is called fluorescence. The
portion BC is the light emitted after illumination and is called
phosphorescence.
Phosphorescence may last only for a period of 10-7 seconds,
or for several hours. We are mostly
interested in periods of from 1 to 5 seconds.
There are three aspects of luminescence: -
(1) Absorption of energy of primary bombarding
photons - due to the incident light.
(2) Transfer and storage of this energy.
(3) Conversion of this stored energy into light.
A crystal consists of a regular array of ions. (You can imagine a large box filled with
billiard balls which have been packed in a regular and tidy fashion). In the case of calcite; these balls represent
calcium and carbonate ions.
Naturally occurring crystals are rarely pure, however, and
an impurity will cause a local disturbance in the array (you can imagine this
time a larger ball such as a tennis ball in the middle of your box of billiard
balls). Such an ion is called an interstitial
ion and plays an important part in luminescence.
Now let us look a little further into the structure of these
ions. For our purposes, the ion can be
considered to be a nucleus surrounded by a number of mobile electrons. If an electron gains some energy, it will
tend to move away from the nucleus and become less stable. In general, if an electron gets the chance,
it likes to lose energy and become more stable. The electrons, however, cannot be at any distance they like from the
nucleus, but must go round it at one of a number of fixed radii which thus
divide the electrons into a number of shells representing different energy
levels. We shall consider two of these
outer shells or bands which are
.
(1) The Valency band, which is the highest normally
filled band, and...
(2) The conduction band, which is the lowest
normally empty band.
The difference in energy between these two bands is called
the gap energy and is written Eg. Now,
if a photon with energy hv, being greater than Eg is incident upon the valency
band, it can transfer its energy to an electron, which can then jump into the
conduction band, leaving behind a hole in the valency band, as in figure 2.
Figure 2.
Remembering that an electron likes to be stable, we should
not be surprised to find that the hole rises to the top of the valency band, as
it is displaced by electrons above it - rather like an air bubble rising to the
top of your beer (not if you drink draught: -Ed). The electron-hole pair is called an
Exciton. The exciton cannot conduct
energy, but it can transfer energy because it is mobile. This excitation is therefore different from
the excited state of an impurity ion which is fixed.
Figure, 3 shows the life of an exciton as it wanders about
the crystal
.
Figure 3.
Now and again the electron will fall into a trap. This is an interstitial ion which, you will
remember, has produced a local disturbance in the energy levels present. Then, by chance, the electron will gain
enough energy to jump back into the conduction band and continue its
wandering. Eventually, it will be
trapped in the excited state of an interstitial ion, which acts as an
activator, or luminescent centre.
Recombination now takes place. The electron is first trapped and then the
hole is trapped (an electron from the impurity fills up the hole) and the
interstitial ion regains its ground state. In the process, a photon is emitted.
The nature of the impurity affects the time for which the
exciton remains trapped and also the colour of the emitted light, which is
always of a greater wavelength than the incident light. It is known that Strontiamite, SrCO3;
Magnesite; MgCO3; Dolomite CaMg(CO3) and some forms of calcite luminesce under ultra violet light. Further work may discover the impurities
which produce this phenomenon and hence throw some light on the formation of
these crystals.
Caving Log
13.1.62. Swildons. Mike Luckwill + 3 from
14.1.62. Eastwater. Mike Luckwill, G.Dell, J. Cornwell + 3 from
14.1.62. Eastwater. Mike Palmer, Mike Weadon. Followed
'clothes line' all the way. Fings
definitely ain't wot they used t'be!
15.1.62. Eastwater. M. Luckwill, J. Giles. Trip to
retrieve camera.
3.2.62. Eastwater. Dell and J. Cornwill.
3.2.63. Swildons. Mike Boone, Ron Wyncoll.
3.2.62. Cuthberts. P.M. Giles + 11
3.2.62. Cuthberts. Mo Marriott, John Eatough and John Attwood. 11 Derbyshire types. Tourist trip.
4.2.62. Cuthberts Mikes Wheadon and Palmer, Albert and. 4
4.2.62. Balchs
Hole. B. Prewer, P.M. Giles, M. Baker, G. Pointing, D. Berry, M. Boone, G.
Selby and several M.N.R.C., and Cerberus types. Photographic.
10.2.62. Cuthberts. Bryan Ellis and Chris
Falshaw + 9 from
11.2.62. Balchs
Hole. Mike Baker, Alfie Collins and Jill. Photography in Maypole and Pool
Passages. Mem. Collins must take
alternative means of illumination.
11.2.62. Cuthberts Survey trip in Cerberus Series, closed traverse almost completed. Damaged tripod stopped further surveying. Keith
Franklyn, J. Eatough, N. Petty and
11.2.62. Cuthberts. John Attwood and Eatough started to take the latter's maypole down, but
two lengths were, too long. Photographic
trip instead. Taped the drip pockets in
Curtain Chamber.
17.2.62. Cuthberts P.M. Giles, Mike Holland, L. Holland and 5
18.2.62. Lamb
Leer. J.M. Calvert, J.Ransome, G. Tilley, G. Owen, R. Roberts, A. Leysham, C.
Peters, H. Rowley.
18.2.62. Balchs
Hole. B. Prewer, P.M. Giles, G. Pointing, D.
24.2.62. Heale
Slocker. Coffee and occasional digging, very nearly in: M. Baker, M. Luckwill, P.M. Giles.
25.2.62. Cuthberts P.M. Giles, M. Luckwill, R. Pyke, P. Badcock. 24' of maypole transported to Upper Traverse
Chamber and left at top of the pitch for use in Hanging Chamber. This was followed up by a quick trip into
September Series where a small hole at the lower end of the bedding plane which runs down the side of September
Chamber was entered and found to join up via a large and rather well decorated fifth with the main chamber again at
floor level.
25.2.62. G.B. Photographic trip to Gorge and Helictite Chamber by J. Attwood, J.
Eatough, H. Phillpot, J. Cornwill. Noted
with DISGUST the considerable deterioration in Helictite Chamber.
25.2.62. Heale
Slocker. M. Baker, M. Luckwill, P.M. Giles, P. Scott, J. Hill. We are in! About thirty feet of passage ending in a choke, the floor of which is
composed of large boulders and mud infill. Passage appears to be going steadily down the dip.
3.3.62. Cuthberts Bryan Ellis took a party of M.C.G. on a "Grand Traverse" down
Pulpit Pitch and Main Stream to duck, out via Cerberus Series and Wire Rift.
3.3.62. Swildons. Mike Luckwill, Bob Pyke. Surveying
extension past Keith's Chamber.
4.3.62. Cuthberts Mike Baker, Bruce and 4 Redland Tourist trip which included
4.3.62. Cuthberts N. Petty, B. Wilson, J. Williams, M. Rogers, S. Godwin, B. Hargill, B.
Parrell. Both Tourist trips.
4.3.62. Cuthberts M. Luckwill, Pat Irwin, plus 4 '
4.3.62. Goatchurch
& Sidcot G. Tilley, J. Ransome. Quick trip
to get rid of the Camera Pox.
4.3.62. Cuthberts R. Roberts, R. Croft, C. Peters, H. Rowley. Finished the survey of September Series.
7.3.62. Eastwater. M. Baker, R. Roberts plus six. While on the above trip, I noticed a
peculiar formation. It was about half an
inch high and formed by spent carbide. Condensation had caused a water drip to form on the carbide which had
produced a "stalagmite". The
formation was very delicate and the walls were almost transparent. M. Baker.
17.3.62. Cuthberts J. Hill, Peter Scott and 8 U.B.S.S. Tourist.
18.3.62. Balchs Hole Garth, Gordon and Roger.
18.3.62. Cuthberts P.M. Giles, M. Holland, M. Luckwill, J. Cornwell, J. Ransom, J. Williams,
M. Calvert. Thirty six feet of maypole
was assembled below the Maypole Pitch with a view to re-entering Hanging
Chamber to recover the 20' of maypole therein, a lifeline was then run from the
top of the Maypole pitch to a large boulder in Upper Traverse Chamber. The maypole was erected, but after three
changes of position the attempt was abandoned and the may be disconnected and
left at the bottom of Maypole Pitch. In
order to retrieve the maypole in Hanging Chamber, the original method of
maypoling seems to be the only solution, unless a less flexible method of
joining maypole sections is devised which may just permit the direct route.
19.3.62. Nine Barrows Jim Giles and Mike Boone took a brief look at this dig and found that a
partial collapse had occurred but that the shoring was still intact.
42.3.62. Swildons. R. Stenner plus 2 boys to sump I.
Song Competition
1. Competitors may submit any number of songs, the
words of which must be the original work of the competitor.
2. Any songs submitted must, in the opinion of the
organizer, be suitable for performing at the club dinner and must be connected
with club activities.
3. Competitors should indicate how they wish their
songs to be presented. If they do not
wish to sing themselves, a suitable "choir" will be laid on, and
various members of club who can perform on musical instruments will be
available to act as accompanists if desired by the competitor.
4. There will be two closing dates. The earlier, for those who wish their songs
to be sung and/or accompanied for them, will be SATURDAY, AUGUST 25TH to allow
time for rehearsals. For those who wish
to perform entirely by themselves, the closing date will be SATURDAY, SEPTEMBER
22ND to allow for elimination if this should become necessary.
5. If more than about half a dozen songs are
received, it may be necessary to weed out some of the songs, so that people
will not become, bored at the dinner by a long session. In that case, the organizer will arrange for
an impartial judge to pick out the best songs. If this occurs, competitors who may have written their own tunes must
arrange an audition with the judge between the last closing date and the
dinner.
6. Judging of the final selection of songs will be
by popular acclaim at the dinner.
7. A suitable trophy will be awarded to the winner
and runner-up. All competitors whose
songs were presented at the dinner will receive a consolation prize - probably
in the form of a drink.
The rules for the PHOTOGRAPHIC COMPETITION will be printed
in next months B.B. the dinner is on Saturday, October 6th.
Climbing in
Cornwall
- Easter 1962
A large crowd of about thirty assorted members assembled on
the Thursday evening after motoring down under incredible difficulties (cars
travelling in the opposite direction on their correct side, etc.) The venue was Trevalgan farm near St, Ives
where a choice was to be had between camping and staying in the excellent barn
provided.
Good Friday dawned cold and clear and the entire expedition
repaired to Porthmorna Cove on the
After this effort, Marriott, Bennett and Tuck ventured up
Black Slab Climb on Bosigran face. The
slab, which is a conspicuous feature of the face, looks F.N.I. from a distance,
but on closer inspection is found to be liberally sprinkled with holds. According to the guide book, its colour
(black) is due to a coating of 'schorl', a piece of information which appeared
to produce no intelligent response from the climbing party. It was decided by a two to one vote that Mr.
Marriott should lead the slab, which he did after surmounting an awkward
pinnacle.
On Saturday morning, the intrepid explorers 'did' St. Ives
and returned to Bosigran in the afternoon. This time, attention was directed to the Bosigran Ridges on the West
side of the cove. These run down at a
steep angle to the sea and were used for commando training during the war. When the climbers arrived at the seaward end,
ready to do great things, a major setback was encountered. The climb - carefully selected from the guide
book - could not be found. After some
argument agreement was reached as to where the climb ought to have
started. Unfortunately, the rock at this
point was in the form of a smooth vertical wall up which no climb of a
reasonable standard could be found. After several unsuccessful attempts, the climbers retreated muttering
darkly that 'it must have fallen into the sea' etc. Messrs Dunn, Turner and Malcolm departed up
the ridge from a higher start while Marriott, Tuck and Bennett followed after
roping a severe which proved much harder than it looked. By this time the weather had become warm and
sunny and the climbers slowly meandered up the ridge, talking photographs and
making private variations to the pitches. Further on, things became more serious and the final climb caused some
misgivings. This was in the form of an
almost horizontal knife edge, which is climbed to the detriment of certain
parts of the climber's anatomy. The end
of the ridge was so thin that it looked likely to cut the hands, and the whole
thing was quite unlike anything that anybody present had previously climbed.
The next day was spent on the West Coast, starting with
climbs on Chain Ladder. This is reckoned
to be the finest of the Cornish sea cliffs, and the four climbers were quite
anxious to visit it. It is best
approached from the north, where a steep scramble leads to a deep inlet,
bridged by a large boulder. This looks
insecure and was crossed rapidly. As it
was the first visit, two fairly easy chimneys were selected. Initial pitches proved quite straightforward
but some confusion with route finding occurred higher up due to not reading the
guide book properly. Several sea birds
nests with eggs were found and Steve Tuck was nearly attacked by a bird which
we think from its size must have been one of the last surviving Cornish
ostriches.
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Cave preservation in a nutshell from the N.S.S.
magazine..... "Take nothing but photographs - Leave nothing but footprints"
*****************************************
THE CAVE DIVING GROUP REVIEW FOR 1961 IS NOW ON
Containing reports and references to operations in Northern
Pennines; Mendips; Derbyshire; South Wales;
*****************************************
The Belfry Bulletin. Secretary. R.J. Bagshaw. Editor, S.J. Collins.