Kelp Part 1 - from soda ash to iodine

The distinctive cone of an 18th century glassworks in Glasgow

Soda ash - or to give it its technical name, sodium carbonate - is a type of alkali. That's enough science already, it's a chemical used in the manufacture of glass and soap. But in the 18th century it wasn't a mineral that could be mined or quarried. It is now but back then it had to be extracted from plants found in salty environments by burning them to produce ashes rich in the chemical - hence soda ash. The best plants for this purpose were saltworts native to the coasts of the Iberian peninsula and the Canary Islands the ash of which was called barilla. Second best was seaweed found along Europe's north western seaboard which was burnt to form a mineral rich material called kelp.

Kelp burning in Scotland is said to have begun in Fife in the 1690s. It spread to Orkney in the 1720s then the west coast in the 1740s. But it really took off in the 1790s when the Napoleonic Wars closed off imports of barilla from Spain. The price rose from about £7-8 per ton mid-century to a peak of around £22 in 1800 when Scotland was producing about 20,000 tons of kelp a year.

Smoke from kelp burning features in a number of William Daniell's images, this one at Gribun on the west coast of Mull around 1815.

Kelping was a very labour intensive process as about 20 tons of wet seaweed had to be collected to produce one ton of kelp. Whole families - men, women and children - laboured chest deep in the sea cutting weed which was then laid out to dry before being burnt in stone lined pits to produce the valuable kelp, actually a sort of crystalline slag formed when the seaweed melted in the fire then cooled and solidified rather than an ash as such.

An unusually well preserved kelp burning pit in Ardnamurchan - picture credit Heritage Ardnamurchan

Several factors conspired to cause the kelp industry to decline in the first quarter of the 19th century. First, the return of peace in Europe after Waterloo in 1815 allowed imports of barilla from Spain to resume. Second, a process to extract sodium carbonate more cheaply from common salt had been developed around the turn of the century. For a while, tariffs on the import of barilla and excise duties (the same sort of taxes we still pay today on things like petrol, alcohol and tobacco) on salt continued to keep kelp competitive but these were eventually abolished and by 1831 the price of kelp had slumped to £2 per ton.

The collapse of kelping was a disaster for the estimated 40,000 people in the north west of Scotland who had been dependent on the industry. Their coastal smallholdings (these were some of the earliest crofts) were too small to support them year round but there was no alternative employment locally. (For a modern analogy, think of the impact on mining villages of the rundown of the coal industry.) The landowners were reluctant to divide up the large farms (from some of which the kelpers' ancestors had been cleared) but even if they had, it's questionable whether there would have been enough land given the intervening population increase the (relative) prosperity of kelping had contributed to. The result was that many people were forced to emigrate around the middle of the 19th century in some of the grimmest episodes of the Highland Clearances.

Kelp burning on the Shiants by Daniell

But although the kelp industry collapsed in the 1820s, it didn't disappear completely. This is the bit I didn't know - it revived in the 1840s albeit on a much smaller scale and with the kelp now being used as a source, no longer of sodium carbonate for soap and glass making, but of iodine (used in various applications including photographic and medical) and another alkali, potassium carbonate (potash - used as a fertiliser). Glasgow became the centre of British iodine production. In 1845, about 6,000 tons of kelp were imported to the Clyde from the Western Isles, Orkney & Shetland and Ireland. By the early 1860s that figure had risen to 10,000 tons (about 60% of that from Ireland) when the price was around £4/ton. Not as much as the 20,000 tons from Scotland alone at £22/ton in 1820 but a significant industry all the same.

Edward Stanford - picture credit Sussex Photo History

In 1862, a young English chemist, Edward Stanford, published a paper with proposals to improve the production of kelp. He considered the traditional method of burning the seaweed in pits by the seashore to be inefficient and wasted far too much of the valuable potash and iodine which literally went up in smoke. He proposed that, in future, Hebridean crofters' input be confined to gathering and drying the weed which would then be heated in cast iron retorts in a nearby factory. (I don't pretend to understand all the science: you can read it here.)

Whether the retorts in which Stanford proposed to heat seaweed to form kelp looked anything like this, I don't know!

Stanford's paper happened to be noticed by the Duke of Argyll. He was the owner of Tiree which had been a kelping island par excellence during the kelp boom of the turn of the 19th century but had not really participated in the revival of the industry in the 1840s beyond "a few tons occasionally bought at a trifling price by some manufacturer in Glasgow". Unlike the owners of other former kelping islands, Argyll disdained from dealing with the people left redundant by the collapse of kelping by clearance and forced emigration, preferring instead a more gradual process of natural wastage coupled with voluntary emigration. Given Tiree's seaweed resource, he was naturally interested in the prospect of a modernised kelp industry to give much needed employment on the island so he contacted Stanford to suggest he give his ideas a trial there.

Haughty? Moi? George John Douglas Campbell, 8th Duke of Argyll 1823-1900

Thus was born The British Seaweed Company to which the Duke ("a very hard man to deal with" according to Stanford) leased a site for a factory at Middleton on the west coast of Tiree - it was spotting this on the OS maps which got me inquiring into the kelp industry in the second half of the 19th century which I had not previously known about:-

Ordnance Survey 25 inch map via National Library of Scotland

Establishing a factory in a place like Tiree in the 1860s was challenging. Stanford supervised the operation personally and you can read his review of the year 1863 - a "hand to hand uphill combat with trouble and difficulty" - on the excellent Tiree Historical Centre's An Iodhlann website here. Not only were there logistical challenges such as there being no pier at Tiree on which to land kit such as cast iron retorts or evaporating pans (one of which drifted alarmingly far out to sea in the course of being floated ashore), there was an absence of creature comforts including:

no stimulant of any kind sold in the whole island. ... We were much surprised to find no place of convenience in the island, and I was for a long time afflicted with piles and boils from the total absence of fresh meat and vegetables.

Stanford also recounted some of his experiences to the Napier Commission (the one which gave rise to the crofting legislation) in 1883. You can read them here (scroll to paragraph 44379 on page 511 of the pdf) but one particular passage is worth recounting here:-

some [of the Tiree islanders] thought the Sassenach was a Frenchman, and their ideas about Napoleon were still very warlike; indeed, every nationality claimed me in turn. Others thought my object was to dig up the dead bodies, and boil them down for the fat (there was little of that to spare then amongst the living); others, the majority, took a violent hatred against me, because they thought I was an excise officer sent to look after the illicit stills. They would do nothing for me; they would sell me nothing. Bread and meat could not be got; and much fine turbot and halibut was cut up for bait, but not for me. However this did not last long, and I soon got on very well with them; for I had promised his Grace [the Duke of Argyll] to employ the people as much as possible.  

Undaunted, the British Seaweed Company proceeded to open another a similar factory at the head of Loch Eport on North Uist where they paid the landowner, Sir John Orde, £1,000 a year (about £120,000 in today's money) for the exclusive seaweed rights of the island plus the factory site and a small farm to keep the horses employed in carting the dried weed from the shore. (There was also a similar farm on Tiree).

Ordnance Survey 6 Inch Map via National Library of Scotland

North Uist was, in fact, less challenging than Tiree because at least Loch Eport was a sheltered harbour where materials could be more easily landed. The North Uist factory was also fired by locally sourced peat (600 tons a year) whereas, there being no peat on Tiree, coal had to be imported there, another arduous task on an island with no pier. As well as the hotel where "stimulants" and "conveniences" were doubtless on offer, there was also a bank at Lochmaddy. There wasn't one on Tiree which greatly complicated the otherwise mundane task of obtaining cash to pay the islanders for the weed they'd collected - in his evidence to the Napier Commission, Stanford tells of the "schedules" of Tiree sailing smacks involving waking the manager of the Clydesdale Bank at Tobermory in the middle of the night to cash a cheque. And of a clerk being sent out from Glasgow on a steamer in winter with £300 who returned with it about three weeks later after an extensive trip to just about every other island in the Hebrides apart from the one he'd been sent to!     

The kelp factory at Loch Eport

Tiree was worth persevering with, though, because the quality of the seaweed there was much higher than in the Uists. The reason for that was that the Tiree weed was washed up on rocky shores whereas the Uist weed was washed up on the sandy beaches of the west coast of these islands and the sand contaminated it. This brings us to the types of seaweed involved. The favoured species in the late 18th/early 19th century kelp boom when sodium carbonate for use in glass and soap making was the goal was weed of the fucus type. This grew in more sheltered sea lochs and was cut from the rocks at low tide in summer.

Bladder wrack - fucus vesiculosis - was one of the species preferred during the kelp boom

But the weed preferred in the second half of the 19th century when iodine was the goal was laminaria. This is commonly known as tangle but the word "kelp" also applies to this type of weed itself as well as to the ashes of weed (of any type). Tangle was torn from the seabed by winter storms and washed up on western facing shores where it was gathered. The preference for tangle in pursuit of iodine explains why the kelping industry revived in very exposed spots such as Tiree and the Uists but not more sheltered spots like Skye and Mull where fucus had been gathered.

Tangle washed up on a beach on the west coast of South Uist - picture credit Alasdair Campbell

I think I'm right in saying that the end product of the British Seaweed Company's Hebridean factories was kelp - i.e. merely the ashes of the burnt (or rather heated in retorts) seaweed rather than potash and iodine. I think the kelp was transported to the company's chemical works beside the Forth & Clyde Canal in the appropriately named Stanford Street in Clydebank for conversion into the final product. In fact, Stanford lived the rest of his life in Scotland at Glenwood House, Dalmuir (now demolished) and was a magistrate of the burgh of Clydebank.  

The timing of Stanford's Hebridean venture in the 1860s was unfortunate. The discovery of naturally occurring potash at Stassfurt in Eastern Germany at about the same time promptly put an end to the market for that particular product. Then, in the 1870s, iodine, the market for which seems to have been volatile at the best of times, began to become more cheaply available from a mineral called caliche imported from South America.  In 1876, the British Seaweed Company was in liquidation (advert for the sale of the Clydebank works here) but Stanford arranged new finance and the business was rescued and continued under the new name of North British Chemical Company. It continued to struggle, though, and by 1883 when he was appearing before the Napier Commission, Stanford admitted that his landlords had reduced his rent and that he would continue the business "as long as it can be carried on without loss" - when pressed by the Commissioners about whether that was imminent, he was coy. His North Uist landlord, Sir John Orde, told the Commission there simply hadn't been any tangle (laminaria) washed up on the shores of that island that year.

Some islanders preferred to continue burning their own kelp and selling that to Stanford rather than just gathering weed for him. This George Washington Wilson photo shows kelp being burnt on North Uist in the 1880s - picture credit Am Baile 

But if he'd been guarded to the Commission about his financial prospects, Stanford was still optimistic about the prospects for new discoveries. In fact, in the same year, 1883, he patented a new chemical extracted from seaweed, alginate. Unfortunately, no viable commercial application for this had been achieved by Stanford's death in 1899. His North British Chemical Company had already been merged with the United Alkali Company formed in 1890 to group smaller family owned chemical companies - paradoxically, one of the UAC's focus areas was manufacturing sodium carbonate by the process which had put the original kelp boom out of business!

Whether or not directly related to the UAC takeover and Stanford's death, I don't know but the Tiree kelp  factory closed in 1901. There's a picture of it after closure here and it was demolished in 1941 with its materials being used in the foundations of the airfield on Tiree. I presume the Loch Eport factory on North Uist closed around the same time but it was not used in the construction of Benbecula aerodrome and still stands today. It's not a listed building or on any tourist trails but I think it should be:-

Google Streetview here - if you turn to your right, the cottage behind you is called Kelp Cottage

By restricting imports of rival raw materials, WW1 provided a temporary filip for the kelp industry but otherwise it seems to have just bumped along the bottom during the first few decades of the 20th century. Then, in the early 1930s, a trade war between Japan (supplier of seaweed) and Chile (supplier of iodine bearing minerals) slashed the price of iodine. Kelping looked to be finished forever except for one small ember left smouldering and destined to carry the seaweed business on. But as this is getting overlong, I'll continue the story in a subsequent post.

Kelp burning on Tiree in the 1930s - picture credit isleoftiree.com