So in 1749, the replenished and reinforced forces of both sides resumed combat. In North America, British punitive expeditions crippled the Iroquois Confederacy, but only after hard fighting and surprisingly heavy casualties due to the partisan war waged by the Iroquois. The Spanish colony of Nueva Habana, in the delta of the Mississippi, was seized by the British, who proceeded to rid the river of Spanish presence; from there and from Guadeloupe, the British, after fighting off a Spanish assault, landed on Cuba and besieged Habana. The siege didn't go all too well, however, owing to the tropical diseases and the well-prepared state of the Spanish garrison; eventually, it had to be called off. Further west, the Spanish had a minor victory of their own - they seized British possessions in Central and South America (namely, Belize, Mosquito Coast and the numerous territories in Guiana Highlands). Several British raids were also succesfully repulsed.
Throughout the Atlantic Ocean, the British preyed on Spanish trade, while the Spaniards organized a system of convoys to defend their routes; in the end, the Spanish managed to restore safety, but that happened mostly because the British navy was distracted towards the battles near Europe itself. Specifically, the Franco-Spanish fleet that gathered to assist their respective land armies conducting the Second Siege of La-Rochelle had to be stopped. Unfortunately, the Brtiish failed to prevent the two fleets from meeting up; although the French fleet was rather weak, it still did strenghthen the Spanish somewhat, and, more importantly, the Spanish no longer could be caught on the move. Instead, they readily gave battle to Lord Barrington's fleet (Sir Haworth was demoted for his "defeat" and died of ill health and disillusionment soon after) and drove it back (partially thanks to the good Spanish use of their experimental steamships), continuing the siege. On the land, most of Huguenot land already fell, but several strongholds, such as Bordeaux and La-Rochelle itself, were holding out. Yet they seemed, at the time, doomed.
Similarily, the Franco-Spanish forces were advancing through Provence and Brittany; in both, they faced fierce resistance, but pressed on nonetheless. A British expeditionary force prevented them from advancing too far into Brittany, but something had to be done nonetheless, and eventually, it was. William Lennox Richmond's forces embarked on paddle-ships and travelled up the Seine. This was a daring move, but a one that the poorly-led French forces didn't expect at all, and thus fell prey to. Lord Richmond fought his way into Paris in a sudden attack and easily overran the French garrison. King Louis-Phillipe was captured and soon forced to sign peace, ceding Normandy to Britain (so that they could keep an eye on him; besides, it was a potentially-rich agricultural province) and withdrawing from the war, as well as allowing the British to place troops on his territory. Naturally, far from all recognized this humiliating treaty; Louis-Philipe's cousin Henri was particularily angry. He was quite far away in the line to the French throne, but did have considerable holdings in Aquitaine, which was mostly occupied by the Spanish troops. With just a little pushing, he agreed to declare himself king of the newly-declared Kingdom of Aquitaine, a Spanish puppet state. Many French troops in the region pledged allegience to Henri, aware that they didn't really have much of a choice and also angry at the "damnlimeys". France was effectively thrown into a civil war, especially as Louis-Philipe's brother Gabriel tried to take over Paris itself (he failed - he managed to start a rebellion, but it was supressed by the new British garrison).
The British forces now were able to proceed to Gascogne, where they managed to relieve La Rochelle with an attack from the land and the sea. However, Bordeaux was seized by the Spanish troops, and Frédéric II has perished in battle without heirs. A provisional assembly in La Rochelle was declared the new Huguenot government. After some more maneuvering, the "front" stalemated approximately on the line of Northern Rhone-Massif Central-Garonne. Skirmishes and attempts to gain territory beyond that line were made by both sides, but none were too serious until, in early 1750, the British, having previously finally expelled the Spanish fleet from the region, besieged, assaulted (with the help of the local population) and seized Bordeaux.
British attacks on Iberia itself this year were mildly more succesful - several cities were badly damaged by naval bombardments, and in some cases even looted by the Maritimes. The Spanish eventually organized the defenses, both with strenghthened garrisons, militias and naval patrols of the coast. The British weren't yet ready to once more attempt a knock-out blow. But they were preparing.
Meanwhile, in Africa, the British struck out against Spanish outposts, especially the isolated, minor ones in West and Central Africas. Most of those outposts were secured; on the other hand, the British attacks in East Africa were much less succesful, with a disastrous failure at Zanzibar where the local pro-Spanish city-states were, unexpectedly for the British, bolstered by a fairly large Spanish flotilla.
In India, the war has fully turned into a slug-fest, with but occasional attacks on large cities that switched hands quite often.
In Indochina, some interesting stuff happened. The Siamese have invaded and crushed, by mid-1750, the kingdom of Myanmar, in spite of limited British assistance provided to the latter. That is to say, they have taken and looted the capital, and secured control over much of the Irrawaddy valley, but went no further naturally, for that was far beyond their logistical capacity. This proved to be their undoing, as albeit they did manage to fell the Ava Dynasty, they didn't completely finish off Siam just yet. A minor village headman, called Alaungpaya, has started an anti-Siamese rebellion, assembling an ersatz court in his village of Moksobomyo. He managed to make himself the leader of national resistance, and amassed a fairly large army that won several minor victories. However, this army was defeated rather badly at Sagaing, and defeat seemed near even though Alaungpaya managed to regroup. It was then that he had managed to find himself a powerful ally, as powerful (if not more) as the British, though at a price - for the Banners of the Qing Dynasty to lend assistance to the Burmese, the said Burmese had to become vassals. But surely that was better than Siamese rule!
And so, Qianlong's armies set out to reinforce Alaungpaya, and, at the same time, to conquer Siam (there were a lot of armies. Large armies, too. This IS China, you know...). Although before the Chinese forces came, Alaungpaya had to retreat to the northwards, in what was called by later Burmese historians "the Long March", when they DID come the day of Alaungpaya's glory came with them. The Siamese were defeated time and again, and soon, the ruins of the old capital, Ava, were in Burmese hands once more. The Burmese then marched on to take Pegu, but most of their Chinese allies went east. The Qianlong Emperor was not amused by continued Siamese resistance, and it was the duty of his Banners to "amuse" him in that regard.
The Siamese fought bravely, but, by 1752, as the First Oceanic War came to an end, they were already defending the very core of their lands. Thonburi, the capital of Siam, was itself coming under attack. Finally, Siam had to sign peace, ceding some borderlands to the Chinese vassal states of Annam and Myanmar and itself joining their ranks, becoming yet another one of the many tributaries of the Qianglong Emperor. Now isn't that amusing?
Anyway, after some more skirmishes, battles and sieges, the final, decisive naval battle came. The Battle of Trafalgar, also called by some more classically-educated British historians as the "Battle of the Pillars of Hercules". The best of the British fleet came there, with the intentions of forcing their way through the Pillars, or through the Straits of Gibraltar as the more sane of people call them. It was a risky move, but, if succesful, it would grant the British access into the Mediterranean Sea itself. Then, Spain could trully be crushed, with the devastation of its Mediterranean and Atlantic trade at the same time. It was also hoped to draw attention of the Spanish fleet here, and defeat it, so that it could no longer threaten the British operations; thus, the British wanted to kill two birds with one arrow.
Unfortunately, the British underestimated the power of the Spanish fleet. For years now, it was being rebuilt. The Most Catholic Monarch of Spain did everything he could to prepare for this ultimate showdown. He granted semi-autonomous status to Genoa, Catalonia and Portugal, in exchangefor more and more ships, more and more dockyards, more and more sailors. All the warships with the minimum of fighting capacity that could be found were being gathered. With generous funding, provided thanks to the money won by reconciling with the Jewry (the things one has to do for victory...), even more ships were being built, and better ones, and newer ones. All sorts of weapons were being tested - war rockets, submarines, you name it; not much of it worked, but the war rockets at least proved quite useful. The treasury was practically stretched to its limits, with all this construction and maintenance. And now, it was time for it all to pay off... or to be for nothing.
Admiral Estebanez Maria de Hita was determined for the efforts of an entire empire not to go to waste. Upon learning of the British fleet moving to seize Gibraltar and Tangiers, Estebanez decided to try and pin the British fleet down there. He knew that, alas, the British had the lead in quality, but he was determined to make sure that the Spanish quantity, combined with the legendary Spanish fury, would be sufficient qualities on their own. He was also smart enough to understand that the British weren't dumb - despite the over-optimistic promises of his staff, he knew that this situation, with the British fleet almost begging to be surrounded, pinned against the coast and eliminated, was way too good to be true. The British had more ships in the hiding nearby, probably, ready to strike out and trap the Spanish would-be trappers themselves once they engage the main fleet. So Estebanez used the Spanish quantity to find some ships that could be spent to delay the British attacks from the outside. He had made plans for what he termed the "Alesia of the seas", for indeed the battle that he planned, and the battle that actually did happen, bore much resemblance to Caeser's famous siege. One British fleet was to be trapped, and then the Spanish themselves were to ward off the other British fleets.
I shan't bore you with details. Lots of things didn't go according to plan, but the Spanish fared much better than the British expected. The orderly lines of ships were soon turned into a mess, as a desperate, chaotic battle ensued, with lots of boardings, bombardments, everything that could happen in a naval battle basically, even rammings and suicide attacks with fireships. The British and the Spanish threw more and more reserves into the fray. A gigantic section of the sea was crowded with ships, damaged ships, blazing ships, sinking ships... and a few intact ships.
And in the end, Spanish fury and Estebanez' luck just barely prevailed. All those years were not for nothing. Spain has regained its honour, its pride in its fleet. And though that fleet was badly damaged, the British one was even moreso.
Soon after, the Treaty of Lisbon was signed. Peace came. It was, to be honest, rather anticlimatic, and could in some regards be almost considered a Spanish defeat.
Firstly, all colonies were restored to status quo. Without exceptions - all the Spanish colonies were returned by Britain, all the British - by Spain. Secondly, both sides agreed not to incite natives or rebels to attack one another's possessions. Thirdly, in France itself, Aquitaine was reannexed by France, but Spain annexed Languedoc and Britain kept Normandy; Britain also established "protectorates" over Brittany and Gascony. Savoy-Provence returned to status quo. Both sides agreed not to despatch troops to France without the consent and participation of the other; they also, ofcourse, agreed to ensure that France is kept in its current weakened state, yet, on the other hand, doesn't fall to anybody else.
Fourthly, and most importantly, the heretofore unclaimed parts of the world was divided into spheres of influence of one or another of the two great powers. They all kept their colonies, as mentioned before, but in parts of the world within another power's sphere of influence, they had no right to expand further. North America was partitioned along the Mississippi River - everything to the east was British (apart from Florida, ofcourse), everything to the west - Spanish. South and Central Americas were naturally in the Spanish sphere. North Africa was also Spanish, but the West Subsaharan was British. Congo Basin was in Spanish sphere, as was all the land north of the Kalahari Desert; but to the south was the British sphere. East Africa, from Mozambique to Mogadishu includingly, was in Spanish sphere, along with Madagascar; but the rest of the Horn of Africa was in British sphere (Britain by then signed numerous treaties with Abyssinia, so it did have much influence there). The western 1/4 of India was in the Spanish sphere; the rest, in British. East Indies and Indochina were in the British sphere too.
The true significance of this war was that the two great colonial powers, the only two serious colonial powers still in existance, have in effect signed a new Treaty of Tordesillas, dividing the world. Although the Treaty of Lisbon didn't bring about eternal peace between them, it has regulated their struggles and limited them to local-scale wars, often fought by proxy, and conflicts that for the most part were resolved by diplomats, not soldiers. The two vast global empires agreed to co-exist (warily), and the bi-polar world came into being.