The following is excerpted from Thomas S. Freeman’s masterpiece of historical research, The Glorious Revolution and the Annexation of England: 10 Days That Changed the World, In the Words of Those Who Witnessed Them (New Amsterdam: Elsevier, 1924).
Dr. Freeman is considered the foremost scholar of Het Wonderjaar and the tumultuous era that followed.
Much of what is known regarding the fall of London comes from the memoirs and diaries of John Evelyn. His diary for June 1, 1688  contains the following passage:
An evil, ill-fated day. God save the King.
To-day I sought travel into London for an audience with His Grace, the Duke of Marlborough. My wife, her dog, and her maid Mary accompanied me to the city, for she was most eager to attend Bellamira that evening at the Dorset Garden, as the Earl of Oxford had said that while the players were of unexceptional merit, it was written with excellent wit.
I had been dozing, for my previous night’s sleep had been bedeviled with sour dreams I now know to have been dark omens, when our carriage stopped with a violent jolt. I called to our driver, and thereupon learned we had been stopped not by poor driving but by the Royal Horse Guard, who had commandeered the ferry and surrounding docks in order that troops, horses, and even cannon might be brought within the city. I feared at first that we should be witness to insurrection, but soon learned a force of clockwork fusiliers advanced upon Westminster.
It soon came clear our carriage would not move until the battle was concluded, so I joined our driver and watched from his perch, full expecting a brief and diverting bit of spectacle. I had heard tell of Mr. Huygen’s mechanical men, for they had been the topic of much conversation and concern for several years. Having met several Frenchmen who had fled the conquest of their home nation, I was keen to see the mechanicals with mine own eyes, though not without trepidation…
They are creations of the most remarkable devilry. The Netherlanders’ skill with clockworks is no secret. And the mysteries of Dutch alchemical glasses are also well known, for the spectacle of the Dutch Tears  is a common diversion at salons. But the metal men—may Providence forgive me for calling such comparison to His own work—are something far removed from these curiosities, unquestionably animated by only the darkest magicks…
Though many valiant souls joined the battle, the enemy was implacable. Thus while a most terrible fire had razed the city but twenty years before, it was decided that only the most drastic of measures could slow the Dutch machines. The Horse Guards oversaw the demolition of many buildings and the ruins doused with barrels of tar pitch. Soon great bulwarks of flame stood between Westminster and the Netherlanders’ metal men. The wind did rise and the flames spread. We watched from across the river, smoke stinging our eyes like nettles, the heat on our faces like peering direct into a blacksmith’s forge, and embers singeing our clothes. Terrible was our sorrow at seeing flame and ash claim the city not once but twice in our lifetimes. But though I thought our despair could not be deepened, it was soon after sunset when my wife’s girl gave up a terrible cry like unto a wild animal, and her eyes rolled into her head until they were white as hen’s eggs, and she did faint. For there, moving through the towering flames like Hell’s own demons, the machines continued their assault as though the fires were naught but an invigorating breeze. The heat of the fires cooked the powder in their fusils, but the enemy attackers tossed those aside and engaged the defenders with their evil hands, and thus did visit terrible wounds upon them.
Native Englishmen and -women were not the only persons to witness first-hand the mechanical assault upon the seat of their government. Alain Longchamp, a deserter from the ill-fated rearguard campaign against the Clakker infantry that had dogged Louis XIV’s retreat across the Iberian Peninsula, was a young man of approximately twenty five  when he landed in London in 1685. Thirty years later, on his deathbed, he consented to interviews by historians from the fledgling Université du Québec, who sought to document first-person accounts of the tumultuous period of the Exile. Asked about the day William of Orange’s mechanical troops laid siege to London, he shared the following reminiscence:
That morning the blacksmiths’s boy came running in a state of great agitation. He carried a pair of brass handbells, and ringing these with singular dedication he roused all residents of the quartier  from their homes and places of worship. So great was the tumult that even the priests emerged from their chapel, blinking and wondering.
‘Boy,’ cried one, ‘I know you for the smithy’s lad.’
‘You do, sir,’ he replied.
‘What cause have you for creating such agitation on the Lord’s Day?’
‘It is war, sir. A Netherlandish army has landed in London, having rowed in boats direct from Holland and up the river.’
At this many in the crowd took the boy for a liar, and some even called for him to be whipped, declaring that all reasonable persons knew such a feat to be quite impossible. But he was most adamant.
‘S’truth, sirs, upon my oath it is. The Netherlanders have sent soldiers of most peculiar disposition, for their skin gleams like the metal of these bells and it yields to neither blade nor musket ball.’
Upon hearing this, the women set to wailing, for we had told the tale of our flight from the Dutch machines to any and all. The priests kissed their beads and prostrated themselves in the very street in prayer to the Blessed Virgin, and Gray’s Inn Lane  was awash in the tears of Frenchmen. Those men loyal to James and ignorant to the nature of the metal demons made haste to the river, thence to Westminster, some with naught but their blades, some with less, all contrary to our good advice and experience. I believe they made many widows that day. Many exhorted us to join arms and absolve ourselves of the conquest of our home, and called us cowards and cravens when we did not, but knowing this to be folly, and having survived such disastrous conflicts in Spain only through the Grace of God, we disregarded these slurs.
Thus ended our brief sojourn in England. We quit the quartier that afternoon, intent on Wales and from there found passage to Ireland. Knowing the Irish Sea too slight an obstacle for these accursed mechanical men, we continued soon thereafter to the New World where, it was said, Vauban and His Majesty had found refuge among the natives. 
 As it is known the assault on Westminster and subsequent fire took place in mid-May, the date here suggests Evelyn’s account is not a true diary entry, but a memoir written after the fact.
 Known more commonly as “Prince Rupert’s Drops.”
 This is an estimate, based on rank and typical ages of military service at the time. As with virtually all members of the so-called génération refugiés (roughly, those born in France in the decades prior to its fall and who fled to the New World in the wake of the Dutch conquest), official records of Longchamp’s birth are inaccessible and may no longer exist.
 A small community of French refugees and campaign survivors who settled in Chancery Lane during the decade spanning Louis XIV’s disastrous invasion of South Holland, the collapse of France, and his subsequent retreat across Iberia.
 The original, pre-Annexation name for what is now Oranjestraat.
 Translated from Beauharnois, L. T. Nouvelle France: Une Histoire. Québec City: Presses de l’Université du Québec, 1888.