Belfry Bulletin Number 208

The Belfry Bulletin

No 208 5

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June 1 9 6

Monthly Journal Of The Bristol Exploration Club

Vol. XIX No.6

Climbing Meets.

Sun. 20th June. AVON GORGE. Meet at Tennis Courts 11am.

Weekend 17.18 July. N. WALES. Camping at Ogwen.

Caving Meets.

Chelsea S.S. Triglay Expedition. Members of this expedition will be on Mendip on July 3rd and have kindly agreed to give a talk and slide show on their 1964 expedition to Yugoslavia. This is of particular interest as the conditions will be similar to those the B.E.C. members will have to face on the trip to Austria.

June Committee Meeting.

The June meeting of the committee finalised the arrangements for the 1965 Annual Dinner. This will be held at the Cave Man Restaurant on Saturday 2nd October following the A.G.M. as per usual custom. For those members who still recall with distaste the last dinner we had at the Cave Man, it should be noted that the conditions are very different now. A slap-up meal has been organised including soup, grilled trout, roast turkey, sweet with a cheeseboard as an alternative and coffee. It is hoped to be able to include a trip round Gough’s after the meal.

It looks as if the arrangements at Redcliffe are in the melting pot at present and it may be necessary to change our Thursday meeting place in the end. Bob is negotiating at present for an acceptable deal at the Church Hall before we consider any other arrangements.

Other business included the construction of the new toilets and the provision of dustbins for a regular collection by the council. _______________________________________________________________________________________

Slit –Sided

Stalactites

…by Jill Tuck While looking over two lead mines on a hill near Machen, a few miles North of Newport, we noticed a type of stalactite formation which I do not recall seeing before, and I have therefore sketched some typical forms for the record, in the possibility that others mat recollect seeing them elsewhere.

Shape and Texture.

Hard cave stal. not the soft growths more usually associated with artificial excavations. From pottery found, it is almost certain that they have formed during the last nineteen hundred years. “Snow” formations are frequent throughout the mines on all the flows, and many of these stalactites have “snow” on them, sometimes with minute stal. nodules in small or large patches. Some stalactites have snow built up inside and have a snow free exterior: others vice versa but, as many others are free of snow entirely, it seems there is no significance in this. Others again, have the interior lined with a different colour stal. from that of the exterior.

Page 2 It will be seen from the sketches that many of the stalactites begin with a narrow neck (About the diameter of a straw) which then widens very rapidly into a bell or boot shape, nearly always slit up one side.

An irregular line is often seen down the stalactite, representing a previous slit which has since been closed as the stalactite grew.

Other types of this stalactite formation begin immediately from the roof, as in diagram 6, with a water drop that seems about twice the diameter of the usual drip. Often, inside the stal. deposition being built up in a roughly round shape, there is another lump or line of stal. so that, when viewed from below, the stalactite has the appearance of the underside of a slug.

SLIT-SIDED STALICTITES (Acutal Size) 1. Irregular straw with slit end.

2.

Boot shape, widely open at the bottom. N.B. Black areas represent inside of stal. in all cases.

4. Complex slit stal.

Positions of slits can be seen in at four places.

The top ½ is crystalline straw

6. There other typical forms ordinary straw for comparison.

3. Boot ended helictite (the projection at the side is made up of minute ‘snow’ nodules

5. Helictite solid inside except for pinhole through

with 7. Twin Helicties united and ending in Bell

Page 3 All types have the heel end filled with water which has passed down through the neck via the usual small space. The edges of the bell arte usually scalloped and are very fragile, but some, in contrast, have edges which are thick and smooth. A few noticed were of a more crystallised type with symmetrical ribs leading outward to a regular dog-toothed edge, exactly like a small scallop shell. Inside could sometimes be seen a small needle shaped crystal almost floating inside the water drop. The usual length of the stalactites in from one to four inches long, but others seen were longer and there seems to be no limit to their size except that imposed by time.

Position.

The mines are lead mines in carboniferous limestone, the entrance being on top of the hill, and the galleries from 50 to 150 feet underground with about a thousand feet of passage. The stalactites seem to be of similar type throughout, not dependant on possible temperature or ventilation effects to be expected near the entrance.

General.

About 80% of the formations in these mines are of this unusual shape and it appears that whether the stalactite begins as a straw, helictite or anything else, it always develops this tendency to bell out. There is no correspondence between the slit side and the air flow or general slope of the roof. Probably much depends on the actual mineral content in solution in the water, which again may depend on the type of limestone, and the nearness of these mines to the surface and plant acids.

It seems clear that the sloping bottom edge of the stal. and the side slit are caused by the drip running to one side, but it seems strange that the form is not common in other areas. _______________________________________________________________________________________ Club members certainly seem to be going in for studies in caves nowadays. While Jill sits and thinks about form of stal., the next article cites the case of a club member who, one presumes, just sat….

A Preliminary Psychological Experiment in St. Cuthberts Swallet ………..by Alan Thomas The aims of the experiment were twofold. To examine subjectively one’s ability to function effectively under cave conditions in total darkness, and to demonstrate the effect of such conditions on one’s ability to estimate time.

Thirty hours were spent alone in the dark. I had with me a sleeping bag, change of clothing, food of the kind did not require cooking, and recording box. This consisted of a revolving clockwork drum drawing a slip of paper at a constant speed past a slot. Periodically, I drew a line across the paper and wrote an estimate of the time. Unfortunately, the device stopped some time after estimated midnight, so the record is only of the beginning of the stay. This record, tidied up, is appended with a true time scale.

A nice dry, gravel-floored corner of Rabbit Warren Extension was chosen as the site of the experiment. I was portered into the cave by Andy MacGregor and Douglas Macfarlane on Tuesday, 8th June. Before they left me at 1.45pm, I unrolled my sleeping bag and changed into my dry clothing. As I had not done this sort of thing before, I had a safety line tied to my left wristband to my sleeping bag, so that I could find my way back to the “camp site”. I also had a torch attached to my sleeping bag in case of emergency. In fact, the torch was not used once during the experiment.

At no time did I have any difficulty finding anything, despite the fact that I have a poor visual imagery.

The senses tended to become more sensitive as time continued. For instance, I noted for the time estimated as 5.10pm Tuesday, “Stream can be heard from the end of my string in that direction. I have been

Page 4 there several times, but this is the first time I have heard it.” Similarly, at 4.15 I noted “Kendal Mint Cake flashes when you break it!” I had broken it twice before without seeing the flash. Later, when I ate chocolate, I could see the static discharges from the wrapper quite clearly.

As an ordeal, the experience was very tame. I had no difficulty spending 30 hours alone in the dark. It is a pity the recording machine stopped when it did because, although the record shows a progressive underestimation of the time, my “rescue” party arrived about when I thought they would.

I first got into my sleeping bag at an estimated 7pm on Tuesday and after that seldom left it. I should have thought that, after thirty hours rest, the trip out would have been easy. However, despite the fact that Roy Bennett, the Franklins and Phil Kingston carried all my gear, I found the return journey to the surface very tiring. I was indeed grateful to Joan Bennett for providing a meal and to the Searle’s for a hot bath. It was worth 30 hours alone in St. Cuthbert’s for the excellent service afterwards.

E S TI M A TE D TI

3am 2am 10pm 1am MIDNIGHT 11pm 10pm 9pm A 8pm CT 7pm U 7pm 6pm A 6pm 5pm L 5pm 4pm TI 4pm M 3pm 3pm E 2pm 2pm 1.45pm start

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LETTER The editor has recently received this, addressed to the club members. In fact, article writing has improved very much of late and plans are afoot for a large B.B. next month. Still, it’ll do no harm.

Dear Club Member, In a recent B.B. I saw a letter complaining about the quality of articles published in our magazine. I don’t wish to criticise the writer for putting his thoughts on paper instead of just grumbling like the average club member, but the answer to such criticism is ‘Don’t complain – WRITE.’ Apathy is also a problem. A short while ago, I wrote a series of articles taking quite arbitrary and often extreme views and yet almost no pen was flourished in opposition or agreement with these articles. Could this be apathy?

The editor himself has even provided articles on how to write an article and whilst even I at my great age cannot remember early days in Swildons (I was only a drip then) it’s still a good title for an article and, of course, Stoke is definitely different to Swildons.

Since I only decided to write this missive about 3 minutes ago, it must be obvious that it does not take long to write things. However, I am very loath to commence another series at the moment as my spy system is not as good as it was.

Page 5 In conclusion then, remember the editor will probably publish your article and your name can be immortalised in print. I shall recommence my series next year, all things permitting, so look for the sign of the: ‘Stalagmite’ (CaCO3)