The People of Gibraltar
1727 – Captain Jonas Moore – He Knew How to Economise 

William Skinner and William Green - William Fyers and Ralph Comgreve
Lord Portmore and Peter Durand - Joseph Sabine

The chief engineers of Gibraltar during the 18th century have invariably had an excellent press. General history books of the place are full of references and anecdotes about the exploits of people like William Skinner (see LINK) and William Green (see LINK) and at the turn of the century yet another William – Colonel Fyers. (See LINK)

On the other hand Captain Jonas Moore, who arrived in Gibraltar in 1714 as a sub-engineer to advise the recently appointed governor, David Colyear, the Earl of Portmore – is hardly given a mention.


The New Mole and Fort  (See LINK)   ( 1732 - Jonas Moore )

It was an odd appointment to say the least. Portmore was an absentee governor – a common occurrence in those days – which meant that Moore probably never had any contact with him and was instead probably forced to deal with Colonel Ralph Congreve, an unscrupulous, self-serving individual who was acting Lieutenant Governor at the time.

Moore’s arrival coincided with a relatively innocuous event which nevertheless led to repercussions which have persisted right up to the present day. The ramifications of the taking of Gibraltar by Anglo-Dutch forces in 1704 (see LINK) and the subsequent attempt by Spain to recover the Rock the following year were still quite fresh in everybody’s minds. The signing of the Treaty of Utrecht (see LINK) seems to have done little to remove British concerns that the Spaniards were not about to give up that easily and would soon be making yet another attempt at recovering the Rock.

Perhaps with this in mind, Congreve had ordered his men to take defensive positions at the Torre del Diablo (see LINK) on the east and the Torre del Molino (see LINK) on the west side of the isthmus which almost immediately caused a major diplomatic furore. The problem was that these towers were situated well north of Land Port which Spanish reasoning insisted was land that according to the Treaty of Utrecht was not part of Gibraltar.

Congreve on the other hand contended that he had been advised by his “engineer” that the towers had to be considered as a necessary part of Gibraltar’s overall defensive fortifications.
Whether the engineer referred to was Brigadier-General Sir Peter Durand - who had recently arrived from Minorca - or Jonas Moore who was also a recent arrival - is hard to tell.



Ships of the Red and Blue Squadrons in Gibraltar – The tower in the middle of the isthmus is the Torre del Molino – the one the extreme left and closer to the north face of the Rock is the Torre del Diable  ( 1721 - Van den Hagen )

What is far less difficult to confirm is that Congreve’s rather loose interpretation of the Treaty of Utrecht was strongly disputed by Spain – with the added confusion of the appearance on several documents of two further towers – La Torre de los Genoveses and la Torre Quebrada. 

Despite trying hard I have as yet been unable to confirm whether at least one of these is just an alternative name for the Torre del Molino mentioned previously. But there is no doubt that there were several towers on the west side of the isthmus.  Regardless of how many towers there were Moore had little need to worry any further when the matter was diplomatically if only temporarily resolved when both sides agreed not to station troops as far as these positions. 


Plan of the isthmus showing Spanish advance trenches during the Twelfth Siege – Two “towers” are shown on the west and one on the east side.  ( 1705 – Unknown )

In any case he was soon packed off to Port Mahon which also happened to be British at the time. He remained there for several years, returning to the Rock in 1720 where he was appointed chief engineer. Two years later in 1722 Captain Moore was promoted to major but not before receiving several letters from the Board of Ordnance in which they congratulated him not just on his ability as an engineer but – perhaps even more importantly - as somebody  who knew how to economise. 

In 1724 the first general survey of the Defences of Gibraltar was authorised by the British authorities. It was carried out by Major Moore assisted by William Skinner who had probably already worked with him during his stint in Menorca. In January 1727 Moore’s ability to keep expenses within approved estimates was again both noted and approved of. 
By February 1727, of course, there were far more important things to worry about than expenses – the Spaniards had decided it was time to try again to recapture the Rock. In February of that year the Thirteenth Siege had begun.


The Thirteenth Siege of Gibraltar

According to G.T. Garratt in his Gibraltar and the Mediterranean:
The most remarkable features of this curious siege seem to have been the number of Spanish deserters and the bad quality of the British guns . . .  78 out of the 126 guns of the Rock blew up.
The question of desertion had always been an odd kind of two way traffic. As Garret himself mentions, a few years earlier, for example, Lord Portmore had argued strongly that the allowance in provision in the garrison was so bad that:
The least diminution of the present allowance of provisions would cause a mutiny  . . . discouraged by recent ration cuts . . . the soldiers were deserting daily.
Despite the poor quality of the British guns they seem to have been able to cause considerable damage to the makeshift positions adopted by the Spanish troops on the isthmus. So much so that overall casualties ended up as being about 5 to 1 in favour of the British which explains why nearly 900 Spanish soldiers deserted during the siege as against only 17 in the opposite direction. 

In June according to an anonymous British officer who kept a diary during the siege and signed himself as S.H. (See LINK):
This night a Colonel of Ireland came to the Head of the Prince’s Line and called to let them know he had a letter for Lord Portmore, but the commanding officer let him know unless retired they wou’d fire at him Sometime after the same person came out of the zigzag beating a chammade and was admitted into the town and deliver’d Lord Portmore’s letters from M. Van der Meer, Minister of the States at the Court of Spain with a copy of the preliminary articles signed by the plenipotentiaries of the several powers of the two alliances for a suspension of arms whereupon his Lordship agreed to it and all hostilities ceased on both sides
The Thirteenth Siege was over – but for Jonas Moore there was still work to be done. In 1728 Lord Portmore ordered a few important changes. The Franciscan Convent on the Line Wall was converted into the residence of the Governor, (see LINK) the block of houses occupying a corner of Main Street (see LINK) and Tuckey’s Lane became a barracks, the Convent of San Juan de Dios (see LINK) a store, and the Convent of the Mercedarios (see LINK) the Admiral’s residence. The Rock’s defences were also to be given uplift.


Crop of plan showing barracks in the corner of Main Street and the Amiral’s residence – here shown as apartments for naval officers  ( 1753 – J. Montressor ) (See LINK)

In 1730 Portmore died and General Joseph Sabine became Governor. More work for Major Moore. Sabine and perhaps others in England seem to have come to the conclusion that the Thirteenth Siege had exposed considerable deficiencies in Gibraltar’s defences. With only a few exceptions these were still dependent to a large extent on the original Spanish fortifications which in turn were based on those created by Moorish engineers centuries previously.


Joseph Sabine

Also in 1730 Jonas Moore sent a letter to his bosses in Newcastle dated 21st November in which he made various comments on the military activities of the Spaniards. He was worried they might affect the security of the garrison:
On the 16th instant two Spanish barks arrived at a battery which they call Tesse and landed a great number of shovels, hoes, pickaxes, etc. 
The 17th they employed one hundred men in raising, blowing and getting together a great quantity of rubble stone at a rock called Las Penas. 
The 18th. we were surprised to see two hundred and fifty men employed in opening a trench (eight foot wide) in the rear of their line of huts where they daily continue them at work, and, by what appears at present, design to run it from the Bay to the Mediterranean in form as it is laid down in the enclosed plan.
Irritatingly there is no trace of the plan nor is it easy to make out from Moore’s comments exactly what it was that the Spaniards were up to. Moore obviously thought the same thing – that is that he hadn’t really made himself clear enough because he followed up his concerns with a second letter. He cannot possibly have had a reply to his original letter as the second was dated just eight days after the first. 
Since mine of the 21st. the Spaniards have carried on their trench in form as it is laid down in the plan enclosed, which we surveyed and find that the line is but one thousand six hundred and forty yards from Willis's battery and by experience we know, that in the last siege, they threw shot from their battery at Tesse to the North Bastion, which is two thousand seven hundred and forty yards distant from the Garrison. 
 I think it is my duty to give your honour my opinion of this new undertaking of the Spaniards as follows:  
1. They intend by making the line of contravallation to cut off all commerce by land and sallies from the Garrison. 
2. It appears by the plan, that they design to build a fort or citadel from whence they will have it in their power (in time of war) to drive our shipping from the present anchoring place to the new mole. 
3. They may from thence constantly annoy the town (and work) to the Parade, with shot and shells from their several batteries. 
4. They will not suffer the fishermen of the place to draw their nets in the Bay or Mediterranean or any cattle to graze without Land Port. (See LINK
5. They will cut off our communication to the back of the mountain. It appears by the above that their whole design is to distress and if possible make this garrison unserviceable to the English.  
In mine of the 8th of April, 1729 I gave your honour an account that the parapets of the several batteries and lines that the Spaniards raised last siege remained as they left them and are so high that they afford cover for an enemy. It's my humble opinion absolutely necessary to level those works before the Spaniards mount their guns in the new works and prevent its being executed. The plans mentioned are not here forthcoming.
All now becomes clearer. The plans which were not forthcoming would have referred to the Spanish fortifications known later as La Línea de la Contravalación which were in the process of being constructed in 1730 under the supervision of Jorge Próspero de Verboom - the Flemish founder of the Real Cuerpo de Ingenieros - and the man responsible for other fortresses along the Bay of Gibraltar. (See LINK)


A proposal for the Spanish Lines by Jorge Próspero de Verboom  (1730 )

A closer look reveals that the plan was the work of Verboom, that the date was December 1730 – a month after Moore’s letter to the UK – and that it is a plan for a project ordered by Philip V of Spain. The line of defensive walls are in the process of being built but the two forts on either end which would later to be named San Felipe on the west and Santa Barbara on the east, are simply proposals. 

Two years later “a series of coloured plans showing the external defences of Gibraltar” was published by Sabine, acknowledging Moore as their creator. I can only surmise that these plans included whatever improvements had been made by Moore during the intervening two years.



The Queen's Battery   ( 1732 - Jonas Moore - Sabine )


Head of Prince's Line, Grand Battery and Old mole   ( 1732 - Jonas Moore - Sabine )


South Bastion and Eight Gun Battery    ( 1732 - Jonas Moore - Sabine )


Sea Line and  Town Battery   ( 1732 - Jonas Moore - Sabine )

The British however seemed powerless to stop the construction work and Verboom’s proposals gradually became fact. Had Jonas Moore managed to stay alive for another half century he would have had the satisfaction of saying to his superiors “I told you so”.   The Spanish Lines – as the British came to call them - greatly added to their problems several decades later when the fortifications were used to effect during the Great Siege. 


The Spanish Lines, here called - La Linea del Campo delante de la Plaza de Gibraltar     ( 1735 - Juan de Sobreville )

Moore remained at Gibraltar until 1740, when he was appointed chief engineer to a joint expedition to Spanish America and died of wounds received during an assault on Carthagena in 1741. Three months later William Skinner succeeded him as chief engineer at Gibraltar.




William Skinner    ( The Convent )