Category Archives: Talks

Telecommunication Submarine Cables for Connecting the World — Rob Peasegood — 6th August 2018

We had a fant­astic talk about inter­na­tional com­mu­nic­a­tions from the speaker’s own per­spect­ive as a tech­nical pro­gramme man­ager for a major mul­tina­tional com­pany which is respons­ible for large pro­por­tion of global inter­net traffic. Rob heads the company’s data centre inter­na­tion­ally. After Tapton school and a degree from Salford University, he worked for BT Global Services, Bovis (as part of the team devel­op­ing Meadowhall and the Manchester Arena) and, more recently, as IT Director for phar­ma­ceut­ical com­pany Wyeth before moving to California.  A real Sheffield suc­cess story!

The first transat­lantic sub­mar­ine tele­phone cable was laid in 1858 but it was a cen­tury later before a con­nec­tion was estab­lished across the Pacific. The world’s first tele­gram was sent by Queen Victoria to the USA pres­id­ent in 1868. The dif­fer­ence now is a fibre optic cable repla­cing the 19th cen­tury copper core insu­lated by a fat seal­ant, rein­forced and made water­tight at great depth by steel, hes­sian and tar.

The Reliance: tansoceanic cable ship. The web­site gives real-time pos­i­tion­ing of any ship­ping. Try find­ing where Reliance is at this moment.

Submarine cables are pre­ferred to satel­lite for tele­com­mu­nic­a­tions because of far greater trans­mis­sion speeds (100ms latency) and the need for two-way traffic. Sky, on the other hand, needs just one-way traffic for global TV trans­mis­sion, and satel­lite is ideal. The 600ms latency for TV doesn’t matter. Light travels very fast through glass (100ms across the Atlantic through fibre optic cable) and is ten times quicker than by satel­lite, where much greater dis­tances through space are involved. Bandwidth denotes capa­city (think of the impact the number of motor­way lanes has on traffic flow).

Internet traffic is grow­ing by 2 per cent per annum and will have doubled by 2021. At present 4.3 mil­lion YouTube videos, and nearly 4m WhatsApp mes­sages shoot round the globe every minute of the day! Extra capa­city is needed (and being planned) for 50 per cent of the rest of the world not yet con­nec­ted to the inter­net (per­haps wor­ry­ing when you think how ancient cul­tures were changed for ever once “civil­isa­tion” intruded … Tahitians, Sub-Saharan Africans, Aborigines, Indigenous Americans etc, etc).

There are numer­ous con­straints to laying under­wa­ter cables; hos­tile weather, deep salt water up to 9,000 metres, fish­ing, wild­life, moun­tain­ous sea beds, tec­tonic plate shift and shark bites (even attack­ing cables). High tech survey ships gauge the depth, topo­graphy, slope, angles, sea bed type and then cable routes are estab­lished. The need for occa­sional retrieval for repair adds to the level of engin­eer­ing expert­ise required. There are 45 cable-laying ships glob­ally and owned by Tyco (who incid­ent­ally in my time were also man­u­fac­tur­ers of sur­gical stap­ling devices very famil­iar to your blog­ger, and which will have fired mul­tiple staples into at least one or two of our Probus mem­bers’ innards). Some 100 pans of cables are in the hold of the cable ship, taking about a month to load, but suf­fi­cient to allow com­plete laying over a single voyage. At $80,000 a day (mil­len­nium prices) the expense of run­ning cable ships is enorm­ous. Ploughs dragged behind the ship cut trenches into the sea bed into which cables are pro­tec­ted in places where they would be vul­ner­able if left exposed, par­tic­u­larly close to shore.

Ships carry a remote vehicle which can des­cend to 2,500 metres either to repair cable on the sea bed or retrieve the affected seg­ment for repair while elev­ated and sus­pen­ded by a series of buoys. Ships are very man­oeuv­rable so they can cope with pre­ci­sion cable lift­ing and laying, par­tic­u­larly in adverse con­di­tions. Nearby ships are warned to stay a mile clear to avoid col­li­sion with the cables as they are lifted.

Some 10 or 11 cable sta­tions (BMHs) are dotted around the UK coast­line where beaches are gently slop­ing, and under con­stant sur­veil­lance. At 50-metres inter­vals along the cable are amp­li­fi­ers. These are powered with sev­eral thou­sand Kv run­ning through insu­lated copper cables incor­por­ated into the fibre optic assembly. The joints are vul­ner­able to damage. We saw a cross-sectional example of a typ­ical fibre optic cable and watched sev­eral excel­lent videos of its man­u­fac­ture Cable is ‘armoured’ where it is exposed to heavy ship­ping, such as in the Suez Canal. Cable pos­i­tion­ing is intric­ate, par­tic­u­larly near the shore, where the ship needs to anchor while the cable is lowered. Laying speeds are vari­able: 0.2km/hr (expens­ive) for armoured seg­ments when divers are in the water and up to 8km/hr (cheaper) when auto­mated in open water.

A key stake­holder is the fish­ing industry. Mutual co-operation is advant­age­ous to both. Fishing boats are used for sur­veys in their own loc­al­ity, which is luc­rat­ive for the fish­er­men, and cables can be sited away from their fish­ing grounds, thereby lower­ing the risk of snag­ging by aban­doned fish­ing gear and anchors cut free in bad weather or from dredging. Most of the risks are close to shore from fish­ing (75 per cent), dredging, and anchors. Seismic activ­ity accounts for five per cent. A dam­aged cable drift­ing away can be loc­ated by voltage shift and its pos­i­tion is con­stantly sur­veyed. Cables get bitten by sharks, and we had an amaz­ing video demon­stra­tion of this. The latest gen­er­a­tion of cables are privately and often jointly owned, due to enorm­ous cap­ital costs involved. Cables fail after 20 or 25 years due to obsol­es­cence, repairs or the hos­til­ity of the envir­on­ment.

Silicon from beach to smart phones by Professor Peter Ivey 30th July 2018


Peter Ivey is a member of Stumperlowe Probus Club.  He gained degrees in Physics at Bristol University before work­ing in BT Labs for 15 years.  In 1989 he joined the University of Sheffield and left in2003 to run his own com­pany in design­ing micro­chips.

His pre­vi­ous talk was an intro­duc­tion to micro­chip tech­no­logy and this talk covers what is spe­cial about silica.  Whilst silica is an oxide of sil­icon and is a major con­stitu­ent of sand, sand is too impure for micro­chip use. The silica used is quartzite (sil­icon diox­ide SiO2) and it is mined.  Oxygen is removed from the sil­icon using high tem­per­at­ure pro­ced­ures to pro­duce poly­sil­icon.  The elec­tron­ics industry uses poly­sil­icon with impur­ity levels of less than one part per bil­lion.  The poly­sil­icon is recrys­tal­lized to grow single crys­tal boules using the Czochralski pro­cess.  It is then dia­mond cut into thin wafers using a “salami slicer”.  These wafers are then buffed using very high powered phys­ical and chem­ical buf­fers to pro­duce the base for the chips.

Peter then explained how a good insu­lator like sil­icon can become a semi­con­ductor.  It has an atomic number 14.  Four of its four­teen elec­trons reside in silicon’s outer shell and com­bine with eight other elec­trons form other atoms to form a tight bond.  If a phos­phor­ous impur­ity (one part in 10 bil­lion) is intro­duced, Phosphorous has one more elec­tron than Silicon and this “spare” elec­tron can flow from neg­at­ive to pos­it­ive (N type).  Boron on the other hand cre­ates a “hole” and per­mits a flow from pos­it­ive to neg­at­ive (P type).  Electronic chip man­u­fac­ture is all about purity.

The cir­cuits used in chip man­u­fac­ture use extremely fine pho­to­litho­graphy.  Copper is the con­ductor used to fill the depres­sion cre­ated con­nect­ing the bil­lions of tran­sist­ors.  There might be twenty layers of con­nec­tions all sep­ar­ated by insu­la­tion layers in a smart­phone chip the size of a thumb nail.  There will be sev­eral miles of “wires” between tran­sist­ors in such a chip.  The gaps between cir­cuits is so small that a single dust particle could cause a short cir­cuit.

The need to pro­duce elec­tronic chips in such a pure and clean envir­on­ment means that the factor­ies are incred­ibly expens­ive and are few and far between.  They pro­duce chips to cus­tom­ers’ designs.  Whilst the man­u­fac­tur­ing machines are enclosed in a very pure envir­on­ment, they require fre­quent main­ten­ance, so the sur­round­ing envir­on­ment must also be as clean as pos­sible for when the engin­eers access them.  An ordin­ary atmo­sphere could take weeks to clean to the required level for the machines.

Peter’s talk was a bril­liant insight into a world at the core of our modern exist­ence.  He guided us through quite com­plex tech­no­logy in a way that his audi­ence could grasp.  He was inund­ated with ques­tions that means that no one was sleep­ing.  An excel­lent talk!

Typhoid in Croydon 1937 — “Who Dun It?” — Peter Watson — 23rd July 2018

We take for gran­ted a clean, safe water supply. Infected and pol­luted water can kill. This was the crux of the account of the typhoid epi­demic in Croydon, the out­break first recor­ded on 27th October 1937 res­ult­ing in 43 deaths and 341 con­tract­ing the bac­teria. Symptoms include extreme lucid­ity, delu­sion, intense fever, loss of appet­ite, insom­nia and a rose pink rash with spots.

Positive proof of the origin of the out­break was not given, but the con­clu­sion was that it was caused by pol­luted water from a chalk well in Addington, a suburb of Croydon, from which water was sup­plied to between 36,000 and 40,000 inhab­it­ants. The well, 10 feet in dia­meter and 250 feet deep, was built in 1888. Essential main­ten­ance work was needed on the pumps, fil­ters and brick­work. From the begin­ning of the work until 15th October the water was pumped to waste but there­after, until 3rd November, it was pumped to supply. The repairs were car­ried out by 18 volun­teers who were sewer work­ers with no exper­i­ence of water supply. The men were lowered into the well on a plat­form which also served to trans­port tools, mater­i­als and rubble. To cater for their ‘calls of nature’ a bucket was lowered and raised to the sur­face on the plat­form for urine dis­posal and they were instruc­ted to come to the sur­face for ‘bowel move­ments.’ Clearly, the men were trus­ted to obey these simple instruc­tions. Subsequently, it was dis­covered that one of the work­ers was a car­rier of the typhoid bac­teria.

At the top level enquiry led by Mr H.L. Murphy, all work­ers stated on oath that they fol­lowed the cor­rect pro­ced­ures for dis­pos­ing of urine and faeces, and did not pol­lute the water supply. Filters and chlor­in­at­ors play a major role in the puri­fic­a­tion of water. The fil­ters, eight feet in dia­meter, were removed for clean­ing and main­ten­ance, with the unin­ten­ded con­sequence that the chlor­in­at­ors did not func­tion. The water supply was neither filtered nor chlor­in­ated.

The enquiry under Mr Murphy looked at the roles of senior man­age­ment and in par­tic­u­lar the Borough Engineer and the Medical Officer for Health for Croydon. It found that the remit of the Borough Engineer was too wide for one person and respons­ib­il­ity for water was only one of his many import­ant duties. The Medical Officer believed food was more of a health hazard than water. It appeared that these two officers had little or no con­tact or com­mu­nic­a­tion with each other. It was no wonder the water supply was neg­lected, res­ult­ing in no pro­ced­ures or doc­u­ment­a­tion for water samples, chlor­in­a­tion and the gen­eral qual­ity of the water supply.

The need for a public inquiry was dis­cussed in Parliament. This was the account from Hansard on 18th November 1937

The enquiry con­cluded that the infec­tion was caused by a com­bin­a­tion of factors coming together, namely that the well was under repair, that one of the work­ers was a typhoid car­rier and that the supply water was not chlor­in­ated. Management was implic­ated and cri­ti­cised for not suf­fi­ciently man­aging the water supply and for not having adequate com­mu­nic­a­tions and backup pro­ced­ures and records. This was a major turn­ing point in the gov­ernance of the water industry, with the intro­duc­tion of codes of prac­tice res­ult­ing from a High Court case. Croydon was a major incid­ent in the water industry with fatal­it­ies prov­ing to be a form­at­ive event in making the public and author­it­ies aware of the crit­ical import­ance of a clean and safe water supply. It was a most inter­est­ing talk which promp­ted many ques­tions from our mem­bers.

Local newspapers, community and the rise of social media. Nancy Fielder 16th July 2018

Nancy has been the Editor of the Star and the Telegraph for two years.  Although they once were run by sep­ar­ate edit­or­ial teams they are now under the same team.

The Telegraph star­ted as the Sheffield Evening Telegraph 130 years ago.  It was the first daily paper.  We saw a slide of the front page.  It was not attract­ive and was covered in close print, with head­lines not very vis­ible and no pic­tures.

The front page has been  made more attract­ive over the years and by the Queen’s coron­a­tion showed a black and white photo of her in her robes and crown.  Nowadays, of course, the photos are in colour and the head­lines are in large print so that buyers are attrac­ted, because news­pa­pers are in decline owing to com­ple­tion from tele­vi­sion and the Internet.

Nancy showed us two art­icles from the early papers that illus­trated how life has changed since then.

One was about a bus driver who was taken in front of magis­trates, called Mappin and Hadfield.  The driver was fined 10 shil­lings because his bus was 5 minutes late!

Another art­icle was about a char­lady, who was fined 2s 6d, because she had shaken out a hearth­rug on Westbar after 10 a.m!

Since Nancy became Editor the team has tried to give a pos­it­ive view of the Sheffield area to make read­ers feel good about Sheffield  and the steel industry.  Journalists know that every story can be writ­ten so the it boosts up or knocks down.  The Star and Telegraph try to put a pos­it­ive slant on local stor­ies if pos­sible.

The Star has a web site on which all stor­ies coming into the office are pub­lished, but the report­ers and edit­ors have no con­trol over the number of web hits.  A few days ago the most hits were on a story about a 10 year-old boy who was taken ill at a scout camp.  ( It was on page 7 in the paper.)  The second place on the hits list was a story about par­ents being upset about the demise of the ‘Build a Bear’ shop in Meadowhall!  There are very few hits on polit­ical stor­ies.  It seems that younger read­ers, who chose the Web over news­print, are not inter­ested.

An example of trying to boost Sheffield was an illus­trated art­icle that appeared recently in the papers about a Sheffield firm, who still make tuning forks under the head­line, “Steel City still hits the right notes”.

The ori­ginal offices and print shops of The Star and Telegraph were on High Street in the ‘Telegraph Tower’, now owned by Santander.   They moved to York Street, but the presses were moved to Dinnington sev­eral years ago.

They print 150,000 copies of the papers, but more people look online- about 350,000 each week with 163,000 fol­low­ers on Facebook.  Money is made from advert­ising online, but less than 50% of that made from advert­ising in print.

Nancy told us how the papers are pro­gress­ing.  Responses from the public to the let­ters page tend to be pos­it­ive but not so on social media.  The edit­or­ial policy is to be neut­ral but com­plaints come in about bias — in favour of the tree pro­test­ers or in favour of the coun­cil, in favour of Sheffield United or in favour of Sheffield Wednesday, in favour of the new Mayor or against him etc.   It seems very dif­fi­cult to report the news without someone feel­ing that the papers are show­ing bias.

Questions from the audi­ence were mainly about pages that are in the papers or that used to be in.

The Telegraph used to have prop­erty pages and now does not.  Nancy said that people gen­er­ally look on-line now if look­ing for prop­erty and there has been a massive impact on advert­ising rev­enue.

Another ques­tion was about the res­taur­ant  and dining-out page.   Nancy said that this was very pop­u­lar, pre­sum­ably because people  eat out nowadays much more than they did in the past.

She said that the main com­plaints (other than bias)  that the papers receive are:  if their weather fore­cast is not accur­ate or if they make a mis­take when they pub­lish the answers to the pre­vi­ous edi­tions’ cross­words!

The Star and Telegraph do not cover national news, although they did in the past.  We saw sides of the Titanic Disaster, Scott’s South Pole Expedition, the King decides to abdic­ate but the big stor­ies were local — the Flying Fortress crash in Endcliffe Park, the Battle of Orgreave, Park Hill Flats apply­ing for listed status and the World Student Games.

Nancy fin­ished by saying that The Star per­forms well for a daily paper but cannot be com­pla­cent.  Who would report local news if these papers close?  Look North does not have a journ­al­ist in Sheffield, and although Radio Sheffield has 5 journ­al­ists their news tends to be brief com­pared with the writ­ten page.

We found this a very inter­est­ing view into the local news­pa­per industry, as was demon­strated by the many ques­tion from the audi­ence.

AMRC — the first fifteen years — Rab Scott 9th July 2018

Our speaker this week, Professor Rab Scott of Sheffield University, is the Head of Digital and vir­tual real­ity at AMRC, loc­ated at Orgreave on the Rotherham/Sheffield bound­ary. Not so long ago this was the loc­a­tion of a major indus­trial dis­pute which looked to the coal-dependent past but now looks to the future and the begin­nings of a ‘Fourth Industrial Revolution’.

 Rab was to revive memor­ies of a fas­cin­at­ing visit made to the Centre by sev­eral mem­bers about three years ago.   A geo­lo­gist by early aca­demic back­ground at Glasgow and Sheffield Universities, his career has taken him all the way from study­ing the earth’s raw mater­i­als to lead­ing research –appro­pri­ately in Sheffield -at the cut­ting edge of present and future indus­trial devel­op­ments which seek to max­im­ise the poten­tial of mater­i­als and man­power.

Rab began his present­a­tion with a brief resume of the indus­trial envir­on­ment and the deep routed weak­nesses in the British eco­nomy which AMRC and other centres of excel­lence are seek­ing to over­come. Although we could do with more James Dysons, British invent­ive­ness and research was alive and well.  Persisting prob­lems, included a lack of com­pet­ive­ness and grow­ing trade defi­cit in man­u­fac­tured goods, low pro­ductiv­ity in per­son­nel and plant.  He thought other factors were inad­equate public infra­struc­ture, the gap between aca­demia and wealth cre­at­ing industry, ignor­ance and lack of interest in the work­ing world and ‘hands on’ occu­pa­tions by too many par­ents and teach­ers. While we need to encour­age more girls to con­sider a career in engin­eer­ing there have been a number of pos­it­ive ongo­ing responses such as the STEM ini­ti­at­ives in schools and a recent improve­ment in Treasury and local author­ity atti­tudes.

Our story began in 2001 when a small local com­pany was trying to sell Sheffield made cut­ting tools to Boeing who at the time were seek­ing to get out of the direct man­u­fac­tur­ing of com­pon­ents and move to a ‘just-in-time’ supply chain.  Having been shown the door sev­eral times the per­sist­ent owner finally per­suaded his cus­tomer to trial his cut­ting tool. Boeing finally agreed and were so impressed that they offered to go into a research part­ner­ship and in due course accep­ted the basis that other part­ners ( includ­ing rival man­u­fac­tur­ers) should be involved and make a fin­an­cial con­tri­bu­tion. Other, smal­ler firms, were also encour­aged to join. At this point Sheffield University came on board, and, armed with the spe­cified risk fin­ance what became AMAC was able to draw Government ‘match fund­ing’.

Such enter­prises as joint industry-academic centres of excel­lence in peace­time take, like seeds, a little time to grow and mature. The first build­ing, on the site of the Orgreave coking plant, was opened in 2004.  We were shown pic­tures of the deliv­ery of new machinery which was man­oeuvred through the entrance with a margin of 10cms -a good omen for an organ­isa­tion ded­ic­ated to pre­ci­sion and accur­acy!

AMRC was now to enter a period of encour­aging growth and over the next ten years or so was to add over 100 par­ti­cipants to its port­fo­lio. It was to gain a Queen’s Award in 2010.   More photos were shown of the devel­op­ing site , includ­ing the now redund­ant wind tur­bine which had design prob­lems of its own!  The Centre began to fea­ture on the vis­it­ing list of the great and good includ­ing Royalty (more pic­tures). Prince Andrew has taken par­tic­u­lar interest, open­ing ‘the fact­ory of the future’ in 2006.  Research facil­it­ies or high value or ‘ Catapults’ were to mul­tiply over the years from the ori­ginal ‘cut­ting’ tech­no­logy to cover such fields as cast­ings, com­pos­ites (such as graph­ine), digital elec­tron­ics, robot­ics ( includ­ing arti­fi­cial limbs and hands), cobots,  nuc­lear, and arti­fi­cial intel­li­gence all housed in their own spe­cial­ist facil­it­ies.  These have now spread to the other side of the Parkway onto the Airport site.  

 Rab  out­lined sev­eral examples of the research being under­taken. In the air­craft industry, weight equates to fuel costs (one kilo­gram equals US $ I mil­lion over the life of an air­craft)  res­ult­ing in much effort to reduce the weight of everything from seats, engine cast­ings and land­ing gear  while improv­ing strength and reli­ab­il­ity.  Here there are cros­sov­ers with auto­mot­ive and it is thought that Maclaren’s decision to open a car pro­duc­tion nearby was much influ­enced by the Centre’s impact (they are moving pro­duc­tion of com­pos­ite panels from Austria to Sheffield).  Major firms involved in col­lab­or­at­ive pro­jects have grown from the ori­ginal Boeing (who now sup­port 20,000 engin­eers in the UK) to include BAE, Rolls Royce, Renishaw, Seimens and Toyota.  (see logo col­lage at top).  Some of these firms are involved in high secur­ity defence research and are not open to vis­it­ors.

In con­clu­sion our speaker  shared his vision for the future, telling us about AMRC’s latest devel­op­ment, ‘Factory 2050’ . This devel­op­ment will look over cur­rent hori­zons to anti­cip­ate the impact of cur­rent and anti­cip­ated tech­nical devel­op­ments and trends into the longer term.  It will lead research into the impact of a switch from a man­u­fac­tur­ing to a ser­viced based eco­nomy in the sense that most goods will become ser­vices. Supply will move on from ‘just in time’ to anti­cip­a­tion of require­ments. It will become data driven world.  He gave the example of Xerox copy­ing machines, linked to their pro­duc­tion facil­ity, that will auto­mat­ic­ally result in supply of con­sum­able powders etc based on paper usage.  Appropriately for hot weather, brew­er­ies will be able to fine tune the pro­duc­tion of lager instead of build­ing up unsale­able sup­plies. It will be a world, he pre­dicted, where con­trol sys­tems and soft­ware engin­eers at long last received the same sort of status as Doctors and Lawyers.  This was begin­ning to be reflec­ted in the improved salar­ies they received.

Professor Scott’s present­a­tion was warmly received by mem­bers, reflec­ted in the many ques­tions asked which ranged from the impact of Brexit to the out­look for industry in our city.  His responses were encour­agingly optim­istic and pos­it­ive.  We were left with the feel­ing that while the future might not be orange it could be bright for Sheffield.

















































There’s more to walls — Trevor Wragg — 2nd July 2018

I sup­pose it all depends who you believe – Pam Ayres or Trevor Wragg.

To quote my favour­ite female poet’s odd ode: “I am a dry stone waller, all day I dry stone wall. Of all appalling call­ings, dry stone walling’s worst of all.”

I can’t for a minute ima­gine Trevor Wragg voicing those sen­ti­ments. Trevor lives and breathes dry stone walling, and has been a pro­fes­sional at the job for many years. He was the British cham­pion in 1996, and holds the Dry Stone Walling Association’s Master Craftsman Certificate.

Trevor, who is just coming up his 70th birth­day and lives at Hartington, in the Peak District, is a qual­i­fied instructor and exam­iner with the DSWA, as well as serving on that body’s Skills Committee and being an assessor with the National Proficiency Testing Council and the Dales Agricultural and Rural Training Ltd (DART).

Trevor at work on a length of dry stone wall

He has led assess­ment days for officers from the Department of Food and Rural Affairs (DEFRA) and the Peak District National Park Authority, advising them on both good and bad work­man­ship for grant aided work.

So he clearly knows his stuff, and was just the man to come and talk to us about a fea­ture of the coun­tryside that most of us see almost every day without really think­ing too much about.

His style of present­a­tion per­haps wasn’t everybody’s cup of tea. Rather than wait­ing for his audi­ence to ask per­tin­ent ques­tions at the end of the 80 minutes, he squandered some of that time by asking us ques­tions from his slides to which he knew few, if any, of us would know the answers, so there were many preg­nant pauses.

Even so, we learnt a lot during the present­a­tion. Personally, I thought that a dry stone wall was a dry stone wall. But you could take Trevor blind­fold to any part of the coun­try and, by look­ing at the walls, he could tell you in an instant whether he was in Caithness, Cumbria or the Cotswolds, or his native Derbyshire.

Trevor took us on a pictorial tour of the White and Dark Peaks and Staffordshire Moorlands, point­ing out the dif­fer­ent size and shape of fields enclosed by dry stone walling, and explain­ing how these came about, from the per­fectly straight ‘strip’ system of farm­ing to large, gradu­ally curving fields which gave a team of eight oxen enough space to turn round.

One of the few cor­rect answers from the floor was that sphag­num moss, found in abund­ance on dry stone walls, was once used in the pro­duc­tion of babies’ nap­pies, because of its absorb­ent qual­ity. There is more wild­life in a dry stone wall than in a hedgerow, appar­ently. And walls har­bour more than 2,000 vari­et­ies of lichen, often a source of food for the said wild­life and also used in the pro­duc­tion of dyes.

Trevor being inter­viewed by Ade Edmondson on the ITV pro­gramme Ade in Britain

And I now know, though he didn’t ques­tion us on this dir­ectly, that a smoot hole is a gap of appro­pri­ate size built into a dry stone wall to allow the free pas­sage of cer­tain creatures (such as rab­bits) but not others (such as sheep). It cer­tainly isn’t in my OED, and I’ve now found out that it pos­sibly derives from the Old Norse word smátta, mean­ing a narrow lane.

You get shoot­ing smoot holes, usu­ally on a grouse moor, and others for rab­bits, ducks and geese, badgers or, simply, water. South facing walls sur­round­ing a court­yard would some­times con­tain bee holes, and others might incor­por­ate hen nest­ing boxes. A drawer stone is one which might look indis­tin­guish­able to all the others but, if you knew where you were look­ing, could be pulled out by the fin­gers and had a hol­lowed out top to con­tain money or the keys to a gate.

The Royal Cypher seen from the middle dis­tance

One of Trevor’s most pres­ti­gi­ous jobs was to design the con­tro­ver­sial EIIR royal cypher which was erec­ted on the hill­side near Edensor, on the Chatsworth estate, to cel­eb­rate the Queen’s golden jubilee. This con­sisted of 288.5 metres of dry stone walling, but built only to half normal height so that the shad­ows cast by the walls on sunny days did not detract from the over­all ‘look’ when viewed from the best vant­age point a mile or more away.

Trevor’s design for the three-way slop­ing site and, bottom right, how it would appear from the best view­ing point

There was more to design­ing it than met the eye (lit­er­ally), because the land where the cypher was erec­ted fell away in three dir­ec­tions and Trevor prac­tised with straw bales before coming up with the final plan which made the char­ac­ters look askew when viewed from close up but per­fectly reg­u­lar from afar.

I per­son­ally, and I sus­pect many other people felt the same, admired the EIIR royal cypher, but the Peak Park author­ity decreed that it had only tem­por­ary plan­ning per­mis­sion and the walls even­tu­ally had to come down.

But thanks to the skill of Trevor and his fellow dry stone wall­ers, most examples of their work will still be around for our grandchildren’s grand­chil­dren to admire. They have been part of our her­it­age for cen­tur­ies, and will con­tinue to be so.