Accessory to War

by Neil DeGrasse Tyson

  So no, astronomical discovery was hardly the main agenda. The earliest telescopes were regarded primarily as aids to reconnaissance—as terrestrial devices, meant to be turned toward the sea rather than the sky and to be used in the daytime rather than at night. Marketed to the Chiang Kai-sheks and Benito Mussolinis of their era, not to the Carl Sagans and Stephen Hawkings, the best of these instruments would have been the prized possession of only a select few senior officers.

  Until the 1630s and 1640s the lightweight, portable, two-lensed Galilean spyglass—the lens near the eye concave, the one nearer the object convex—had the market pretty much to itself. Though relatively small and fuzzy, its images at least arrived at the eye right side up. As later described by Johannes Kepler, an alternative version—with two convex lenses—offered a larger field of view, but the image arrived upside down. For non-hurried astronomers studying space, where there is no up or down, an inverted image is not a crippling disadvantage. But for generals and admirals, who usually do their reconnaissance under pressures of time and position, rapid readability is crucial, whether on battlefield, battlements, deck, or promontory.

  Despite all the advance publicity that attended the spyglass, a few military planners did remain blind to its benefits.17 By and large, though, evidence from around the globe shows that terrestrial telescopes soon figured in a variety of military situations, especially surveillance and reconnaissance.

  In 1615, for instance, following the Dutch East India Company’s sinking of the six-hundred-ton Spanish vessel Santa Ana near Lima, Peru, a Spanish captain who had been taken prisoner and held until the Dutch reached Acapulco, Mexico, reported to Mexican officials that while the Dutch were lying at anchor near a Peruvian port, they had “sighted a vessel through some tubes they carry, by means of which they can see more than six leagues,” or about twenty miles. In 1620 the English colonial governor of Bermuda reported having spent several hours looking through his “perspective glasse” from the vantage point of Warwick Fort, monitoring the approach of a strange ship. In 1626, before entering the harbor of Havana, the commander of a fleet from the West India Company relied on his own anteojo de larga vista to survey the situation. Lookouts aboard the many Dutch vessels plying the seas decade after decade from Java and New Amsterdam to South Africa and South America used their telescopes to scan the horizon for privateers. In seventeenth-century Japan, when Christianity was banned and Christian missionaries were understood to be agents of European colonialism, foreign merchant vessels were permitted to enter the country through only two ports, one of which was Nagasaki, where coastal watch stations were equipped with telescopes for scanning the waters.18

  On land, commanders who had telescopes found they could now exercise a degree of control over fronts several miles wide rather than dashing around for a close-up view of small segments of the battlefield. By the mid-eighteenth century, Frederick the Great, the formidable king of Prussia—who greatly valued detailed maps but believed that “when we can make use of our own eyes, we ought never to trust to those of other people”—took to having his camp set up on an overlook, where he could use his own telescope at his own convenience.19 Meanwhile, four thousand miles to the west, an educated Virginian named George Washington was ordering telescopes from London to help him in his work as a public surveyor and mapmaker and in his efforts to make sure that Virginian veterans of the French and Indian Wars got the “bounty lands” they had been promised.20

  In colonial America, almost anyone who wanted a telescope—or, indeed, almost any scientific instrument—would have ordered it from London or Paris. Many of the men shelling out pounds sterling for a telescope constructed by the esteemed English instrument makers John and Peter Dollond had been born or educated in Great Britain or identified with British interests in the colonies. Others were rebels, members of the Continental Congress, officers of the Continental Army, signers of the Declaration of Independence. In 1776 at King’s College (forerunner of New York City’s Columbia University), for instance, while the president, most of the faculty, and half the students declared themselves loyalists, the college’s Irish-born librarian and tutor Robert Harpur, an astronomer, joined the rebels.

  Gradually the study of astronomy, geography, mathematics, and physics in the colonies gained ground. Usefulness—“an Inclination join’d with an Ability to serve Mankind, one’s Country, Friends and Family,” as Benjamin Franklin put it21—became a major goal of education and scientific inquiry. In 1743 in Philadelphia, Franklin and fellow enquirers founded the American Philosophical Society, dedicated to the pursuit of “all philosophical Experiments that let Light into the Nature of Things, tend to increase the Power of Man over Matter, and multiply the Conveniences or Pleasures of Life.” Four decades later in Massachusetts, a similarly enquiring crew founded the American Academy of Arts and Sciences (whose seal features Minerva, the Roman goddess of both war and wisdom) to “advance the interest, honour, dignity, and happiness of a free, independent, and virtuous people.” Franklin, Washington, and other founding fathers soon joined their ranks.22 And if all that doesn’t make you yearn for yesteryear, consider this: the fourth US presidential election, in 1800, pitted the serving president of the American Philosophical Society against the serving president of the American Academy of Arts and Sciences.

  Before that, of course, there had to be a first presidential election, which was preceded by George Washington’s taking command of the Continental Army in 1775. One of Washington’s early initiatives was the collection of military equipment for use in the field. Clothing and tents were big concerns; spyglasses for his officers were another. As the campaign for control of New York drew near, he also set his sights on getting a powerful telescope through which to observe British camps on Long Island and British ships in the Hudson River. The only one he knew of anywhere in the colonies was at King’s College.

  New Yorkers were pleased to cooperate. The records of the New-York Convention of August 1776—one month after the Second Continental Congress met in Philadelphia and ratified the Declaration of Independence—include the following resolution:

  Whereas his Excellency General Washington is in want of the use of a good Telescope; and whereas a good Telescope is absolutely necessary for the Commander-in-Chief of the Continental Army, to discover the arrangements and operations of the enemy:

  Resolved, That the Chairman of the General Committee of the City of New-York, with such other members of that Committee as he may think proper, take and deliver to His Excellency General Washington, for his use, the Telescope which belongs to, and is part of the apparatus of the College of New-York.

  No. 2. Resolved, That the Convention of this State of New-York will indemnify the governours of the College at New-York, for any injury, loss, or damage, that may happen to the Telescope belonging to the said College.23

  By August 7, the instrument had been delivered to Washington’s headquarters in New York City. Soon afterward, Washington wrote to Brigadier General George Clinton (who would soon become the governor of New York State and eventually Jefferson’s and Madison’s vice president): “By intelligence received and movements observed of the enemy, we have the greatest reason to believe a general attack will be made in the course of a few days.”

  Of course, the mere possession of a telescope to provide intelligence is no guarantee of victory. At the end of August, the British routed the Revolutionary Army on Long Island, and the remaining soldiers escaped to Manhattan Island in the dead of night. On September 5 Washington wrote to Major General William Heath, advising him how to conduct his operations under the dangerous conditions at hand:

  As everything in a manner depends upon obtaining intelligence of the enemy’s motions, I do most earnestly entreat you and General Clinton to exert yourselves to accomplish this most desirable end. Leave no stone unturned, nor do not stick at expense to bring this to pass. . . .

  Keep, besides this precaution, constant lookouts (with good glasses [that is, spyglasses]) on som
e commanding heights that look well on to the other shore (and especially into the bays, where boats can be concealed), that they may observe, more particularly in the evening, if there be any uncommon movements. . . . I should much approve of small harassing parties, stealing, as it were, over in the night, as they might keep the enemy alarmed, and more than probably bring off a prisoner, from whom some valuable intelligence may be obtained.24

  The advice was excellent (the CIA and various writers deem George Washington a first-rate intelligence chief and spymaster), but the results were mixed. By mid-November the British and their mercenaries had taken over all of Manhattan, and Washington’s forces had retreated to New Jersey. By mid-December the much-defeated Revolutionary Army was running out of resources, soldiers, time, and morale. Nevertheless, five thousand or so hungry men and a handful of women under Washington’s command, many of them sick, some of them barefoot, reached the Pennsylvania side of the Delaware River before the worst of winter set in. To make the journey, they had seized every heavy wooden cargo boat they could lay their hands on. Soon the remnants of a couple of other divisions joined them.

  On the windy, sleeting night of December 25, 1776, more than two thousand soldiers made it back to the New Jersey side of the river. At dawn they took the enemy by surprise at Trenton. It was a remarkable turnaround. Emanuel Leutze’s heroic painting Washington Crossing the Delaware—honoring both the imminent victory and the newborn nation—depicts a line of rowboats stretching almost to the horizon, with Washington standing tall and determined in the foremost boat, his right leg planted on the bow as the multi-ethnic crew of revolutionaries struggles with poles and oars in the ice-choked river and light begins to flood the morning sky. At the commander’s left side hangs a saber; in his right hand is a telescope.25

  By the late eighteenth century, the telescope had a recognized role in the waging of war. No first-rate tactician would have engaged the enemy without one. The option of a collapsible midsection—a refinement of the standard hollow tube with its lenses at each end—increased the instrument’s portability. One British optical firm advertised its refracting telescope as having “been favoured with the Approbation of the best Judges in Theory, as well as those Gentlemen whose naval, or military Capacity, has made them more than ordinary conversant with the Use of it.”26 Today, writers of history sprinkle their accounts of bygone battles with references to a long-dead colonel, general, ship captain, or concerned citizen watching in alarm through a telescope as a forest of masts materializes on the horizon, or slowly pivoting a telescope across a landscape like a swiveling gun, or peering through a telescope and muttering, or decisively collapsing his telescope shut once he’s seen what he needed to see.

  The telescope also serves as the key prop in a tallish tale involving England’s most famous admiral, the one-eyed, one-armed Horatio Nelson. In 1801, during the Battle of Copenhagen—fresh from having prevented Napoleon from executing his plans for Egypt and India—Nelson served as second-in-command to Admiral Sir Hyde Parker. Their goal was to break up a Northern European free-trade/free-passage alliance that Britain saw as overly advantageous to France. Parker and Nelson and their fleet were dispatched to convince Denmark, by whatever methods they could muster, to withdraw from the alliance. Parker (who favored caution and negotiation) positioned his ships to the north of Copenhagen and sent Nelson (who favored intimidation to the point of annihilation) and his ships to attack from the south. The battle was fierce and the smoke was thick, but Nelson did not back down. Two hours into the attack, when Parker’s flagship signaled that the British bombardment should stop, Nelson raised his spyglass to his blind right eye and announced that he simply didn’t see the signal. Despite his cautiousness, Parker was killed in the battle, while the confrontational Nelson prevailed. The Danes signed a truce, and the phrase “turn a blind eye” entered the language.

  But the portable terrestrial telescope, even in the hands of a brilliant commander, could not by itself revolutionize war. George Washington, for instance, valued spies even more than he valued spyglasses, as evidenced by a letter of July 10, 1779, in which he writes to a brigadier general, “Single men in the night will be more likely to ascertain facts than the best glasses in the day.”27 A telescope could facilitate the gathering of data about nearby enemy forces, one’s own nearby forces, local terrain, local weather, and local roads. It could facilitate the rejection of some tactics and the adoption of others. But achieving victory in even a single battle remained as daunting, multifaceted, cumbersome, and diffuse a process as ever. A commander with a spyglass might observe an advance contingent of enemy cavalry beyond the next hill or across the river and swiftly devise a method to kill them all, but it would be his lieutenants’ and soldiers’ job to implement his orders. And if the deadliest weapons are effective only when fired at close range, and available cavalry are scarce, the telescope can contribute almost nothing to strategic planning and very little to tactics in the moment. In terms of “who ordered whom to do what, when, by what means, on the basis of what information, what for, and to what effect,” as the military historian Martin van Creveld describes the parameters of military command, the telescope could play only a narrow role. Some prominent historians of war and technology, in fact, accord the telescope no military role whatsoever for its first century or two of life.28

  For starters, consider how land war was waged in seventeenth-century and much of eighteenth-century Europe. Good information was hard to come by, and rapid communication was unknown. Decent roads were few and far between. Maps of any kind were a rarity; countrywide maps that represented towns, roads, and distances at a proper scale were rarer still; and maps that represented the topography were nonexistent. General information about the inhabitants, customs, and features of foreign territories came from a few books, a few newspapers, unreliable censuses, the accounts of pilgrims and merchants and diplomats. Information of greater tactical relevance might come from soldier-spies or from the statements of deserters, prisoners, or peasants; the spy, disguised as a laborer or servant, might enter an enemy camp in the company of a peasant selling turnips or textiles. To ensure the peasant’s usefulness, a member of his household might have been taken hostage.29 Most information not derived from the commander’s own observations traveled to and fro no faster than the fastest horses could gallop. The same speed held for the commander’s orders. Quick decisions premised on up-to-the-minute information were unknown; spur-of-the-moment commands, if ever issued, were unlikely to be executed. Most commands were verbal rather than written, although, before issuing them, the commander may have had to send reports to the king and wait a couple of weeks for instructions.

  Whether his army was tramping across fields or besieging a fortress, the commander’s biggest headaches were securing enough bread, brew, and meat to sustain his troops, providing his many mercenaries with a paycheck and shelter, making sure the horses were fed and watered, and getting hold of enough weapons and ammunition. Thanks to the innovations of Prince Maurice, the troops’ everyday activities, when they weren’t looting the locals or actually doing battle, came to include drill, marching, and ditch-digging. Van Creveld offers a capsule description of the enterprise: “Well into the eighteenth century, battle and warfare were all but identical . . . war apart from battle being almost indistinguishable from a somewhat violent form of tourism accompanied by large-scale robbery.”30

  Portable firearms were relatively new. For every battle in an open field, three or four sieges took place at the walls of Europe’s fortresses, from which a siege cannon sitting on a carriage would fire heavy iron roundshot at the target.31 With the thousands and sometimes tens of thousands of shouting soldiers rushing in and out of formation, the noise of firearms and cannons, the clouds of smoke from exploding gunpowder and flaming siege towers and incendiary devices hurled over the battlements, even a first-rate telescope would have limited impact on the outcome.

  At sea, a telescope could be more useful. All-weather maritime
commerce had been expanding all around Europe since the fourteenth century, and, absent armed protection either on board or sailing alongside, no laden merchant vessel or convoy could expect to reach its destination unmolested. Distant voyages had increased in popularity as hunger for coffee, gold, spices, sugar, slaves, tobacco, tea, textiles, and tax revenues mounted. Most naval battles took place near coastlines, at close range, from which one of the era’s newly large, fully rigged men-o’-war sailing ships would fire its shot from a hundred or more giant cannons. Ships were wooden, and more vulnerable to impact and flame than a fortress wall would be. Because of the closeness of the confrontations and the more limited number of hiding places for a convoy of large ships, a telescope could come in handier than it did on land—if and when the commander was lucky enough to get a break in the fog, smoke, fire, cannonades, and tumult.

  Notwithstanding the many limitations displayed during its first century and a half in battle, the telescope did enable some reconnaissance and did still promise military advantage. Inventors were far from giving up on it.

  Combine a good late-eighteenth-century telescope, a signaling system based on readily visible elements, a capacious code, and a series of relay stations that stretches from county to county, and you get the “optical telegraph,” a signally useful military innovation and the most advanced communications technology of the early nineteenth century. Never mind that it was superseded by the electric telegraph at midcentury. Before it went extinct, local versions of the optical (sometimes called the aerial) telegraph had been built from Stockholm to Sydney, from Curaçao to the Crimea. Some bankers used the telegraph to get a jump on stock quotes. Originally, though, it was meant for admirals and generals.