What can be said of the manner in which the battle of the Brandywine was fought? From a tactical standpoint, was it a “good” fight? A useful lens through which to view this question is an analysis in terms of linear warfare.
Henri de Jomini was a French (and later Russian) general who wrote extensively on the art of war in the Napoleonic era. His writings were a staple at military academies for many decades and are still widely studied around the world. Prussian officer Carl von Clausewitz stressed the political aspects of warfare (war is “the expression of politics by other means”) Unlike Jomini, he argued that war could not be quantified, i.e., made a matter of mapwork and geometry. Jomini’s and Clausewitz’s military principles were laid down in the century following the American Revolution, but their principles of linear warfare and the proper use of arms are directly applicable to the style of warfare waged outside Philadelphia in 1777.
Screening friendly forces and conducting reconnaissances were functions usually assigned to cavalry. Because horse units were capable of faster movement, they were also used to pursue defeated enemy organizations. In the days leading up to the battle of the Brandywine, during the battle itself, and during Washington’s retreat, neither the American nor the British effectively used their cavalry units to perform these roles.
Jomini, a disciple of Napoleon, wrote throughout much of the nineteenth century on linear tactics. His discussions also covered the tactical use of horse units. “As a general rule,” explained Jomini, “it may be stated that an army in an open country should contain cavalry to the amount of one-sixth its whole strength.”1
Jomini believed that the great value of cavalry was its speed and versatility. Such attributes could make a victory complete by breaking up and trapping retreating enemy formations. “An army deficient in cavalry rarely obtains a great victory,” he continued, “and finds its retreats difficult.” When on the defensive, Jomini felt that cavalry could be used to advantage by causing destruction to an enemy elated and disorganized by victory. In contrast to prevailing theory that cavalry’s primary purpose was to screen an army’s flanks, Jomini believed “it may not be regarded as a fundamental rule to post the cavalry on the wings.” As noted earlier, Washington did not post any of his four dragoon regiments on his flanks, and on the morning of the battle held them in reserve near his headquarters.2
A contemporary of Jomini, Carl von Clausewitz wrote on cavalry tactics from the Prussian point of view. Clausewitz argued (and Jomini agreed) that “a serious lack of cavalry impairs the mobility of an army.” In Clausewitz’s eyes, one of its key roles was the pursuit of a beaten enemy. “A body of cavalry or horse artillery with the task of pursuing a retreating enemy or cutting off his escape,” explained Clausewitz, “will find infantry completely useless.” He elaborated his point: “Cavalry increases the mobility of the army. Where there is not enough of it the rapid course of war is weakened, since everything proceeds more slowly (on foot) and has to be organized more carefully. The rich harvest of victory has to be reaped not with a scythe but with a sickle.”3
As far as Clausewitz was concerned, there could never be too much cavalry, nor could it ever be considered a hindrance to the army. However, horse units required significant maintenance, such as the need for proper fodder and blacksmiths to shoe the horses; without healthy horses, cavalry units were next to useless. Because of these factors, the cost of maintaining cavalry in the field made that branch “the most easily dispensable arm.”4
Johann Ewald, one of Howe’s and Washington’s Brandywine contemporaries, wrote about the use of horse units. Ewald entered the German military at the age of 16 during the Seven Years’ War. After the American Revolution, he wrote Treatise on Partisan Warfare in which he discussed reconnaissance: “If an officer is sent into an open terrain for these purposes, the detachment assigned has to consist of cavalry.”5
This understanding of the prevailing thoughts on cavalry tactics in linear warfare makes possible an analysis of how Washington and Howe utilized their available horse units. Washington’s previous limited military experience did not prepare him for what he faced during the Revolution. As historians Allan Millett and Peter Maslowski put it, the American general’s “frontier service had given him no opportunity to become acquainted with cavalry tactics, massed artillery, or the deployment of large forces.”6
In addition to the Continental light dragoon regiments, elements of the Pennsylvania militia mobilized to meet Howe’s invasion were also likely mounted. The only other mounted element in Washington’s army was his personal bodyguard of about 30 horsemen. Taking all these elements into account, Washington probably had between 700 and 800 mounted personnel with him at the Brandywine. (Unfortunately, a more precise number of mounted troops cannot be determined.) His entire army numbered approximately 17,000 troops, which means his mounted element constituted under five percent of his total force—far below Jomini’s recommended level. His deficiency in cavalry (at least according to Jomini’s standard) and its improper use affected the outcome of the battle; Washington did not have enough mounted troops to scout all the roads in the area or properly screen his exposed right flank.
Only two dragoon regiments (the 16th and 17th Light Dragons) were authorized for service in the colonies with the British army during the Revolution. One of those, the 17th Light Dragoons, remained in New York during most of the Philadelphia Campaign and so was not available for Howe’s use at the Brandywine. Three squadrons of the 16th Light were present at the Brandywine. Technically, dragoons were mounted infantry, but they were commonly used as cavalry in North America. These mounted units were used for outpost duty, scouting and reconnaissance, and pursuing a retreating enemy. According to General Howe’s aide-de-camp, Capt. Friedrich von Muenchhausen, the strength of these three squadrons when the army embarked at New York was 300 men. “The two main factors responsible for this paucity of mounted troops,” wrote Matthew Spring, “were the difficulty of procuring suitable horses and the problems of feeding them.”7
Howe’s army also included Hessian jaegers, about 100 of whom were mounted. The Queen’s Rangers, a loyalist regiment, was also attached to Howe’s command. Elements of this regiment were mounted later in the war, but there is no available evidence of them being mounted at the Brandywine in September 1777. Therefore, approximately 400 mounted troops accompanied Howe to the Brandywine. Since his army numbered about 15,200 troops at the Brandywine, the mounted element numbered just two and one-half percent of his force—also well below Jomini’s recommended level.
How did Howe utilize his mounted troops? The three squadrons of the 16th Light Dragoons were divided between the two divisions of the army and thus did not fight as a united force. As one recent historian notes, “Particularly during the campaigns in the middle colonies, what little horse was available was usually parceled out between the different divisions or columns.” The result of this decision was predictable: “general officers often had negligible mounted forces with which to improve an advantage.”8
The available evidence indicates that the dragoons were used to protect moving baggage trains and did not engage in combat roles in the northern theatre. The lack of healthy mounts following the voyage could account for this circumstance. Rarely were they used for scouting or screening moving columns. The mounted jaegers, however, were usually found leading columns of attack, like those at Brandywine attached to Cornwallis’s division. Placed in advance of the main column, they acted as an early warning system.
However, the lack of mounted men affected the outcome of the battle. Once he flanked Washington’s divisions and drove them from the field, Howe lacked the mounted element necessary to conduct an effective pursuit of his routed adversary.
According to Jomini, artillery could be formidable on both the offensive and the defensive. Offensively, a battery could throw an enemy line into confusion, break it up, and by doing so prepare the way for an infantry assault. As he saw it, artillery’s primary value was to shatter an enemy line before attacking it with infantry and/or cavalry. Defensively, artillery doubles a position’s strength by damaging an approaching enemy, raising the morale of the troops around it, and “greatly increasing the peril of approaching near, and specially within the range of grape.” Jomini believed that three pieces of artillery for every 1,000 combatants was the proper proportion for an army.9
Clausewitz argued that artillery intensifies firepower and considered it the most destructive of the combat arms. When an army lacks sufficient artillery, he asserted, the “total power of the army is significantly weakened.” The long arm, however, had several disadvantages. First, it was the least mobile of the branches of the army and thus slowed it down and made it less flexible. Second, artillery required infantry protection because it was incapable of effective hand-to-hand combat. Finally, artillery could be used by the enemy if captured.10
No definitive statistics exist regarding the number of artillery pieces Washington’s army possessed at the Brandywine. According to Jomini, Washington’s 17,000 men should have had 51 guns to assist them. According to one historian, after the Trenton campaign Washington attached two to four artillery pieces to each of his brigades. If this is correct, Washington’s 11 Continental brigades could have had as many 44 pieces with them in September 1777. Without factoring in any artillery that may have been attached to the Pennsylvania Militia Division and any that was held in reserve, Washington would have been only seven guns shy of nineteenth-century standards. Thus, it is entirely possible he met or came very close to Jomini’s standard. However, without definitive primary evidence of the number of guns with the Continental Army, any such finding is somewhat speculative.11
Washington’s artillery performed well during the battle. Proctor’s guns conducted an effective artillery duel at Chads’s Ford. They were overrun due to a lack of infantry support, though not through any fault of their own. The guns attached to Lord Stirling’s and Adam Stephen’s divisions also performed by “greatly increasing the peril of approaching near, and specially within the range of grape.” That remained the case until their infantry support abandoned them and they were overrun. Henry Knox’s pair of small guns performed similar service on a much smaller scale farther south later that evening as Nathanael Greene’s division was taking up its final defensive position.
According to Jomini’s standards, Howe’s army should have had three guns for every 1,000 combatants, or 45 artillery pieces. Much as with the Continental Army, no definitive primary source confirms the number of guns with the British army. Howe had 25 regiments or 35 battalions when counting the grenadiers, light infantry, jaegers, and Guards. Just those regiments should have had 70 guns with them, not counting any reserve artillery. Friedrich von Muenchhausen thought the army had 62 artillery pieces.12 It is highly probable that Howe’s army exceeded Jomini’s expectations for artillery.
The Royal Artillery performed as admirably as Washington’s long arm during the battle. It conducted the artillery duel in the morning well, and provided fire support for Cornwallis’s legions in the afternoon that helped soften up the American line on Birmingham Hill for the attacking infantry. The difficulty of moving the guns, which slowed Cornwallis’s flanking column throughout the day, is the only legitimate criticism of Howe’s long arm.