(^162) Chapter Five
mapped on such a scale as to allow a commander in the held to plan
each day’s march from a map.^18 Nevertheless, as early as 1763 a
French general, Pierre Bourçet, had grasped the possibility, and, in
the ensuing years, actually drew up detailed plans for campaigns along
French borders and for the invasion of England. He prepared a hand
book in 1775 for private circulation within the French army entitled
Les principes de la guerre de montagne in which he explained how a
commander should plan troop movements and supply on a day-by-day
basis from maps; and when Napoleon invaded Italy in 1797 he is said
to have used Bourçet’s plan for crossing the Alps and taking the
Austrians by surprise.^19
Control of army movements by means of maps required a staff of
experts in map reading and logistics. Bourçet understood this and, in
1765, set up a school for training aides-de-camp in the new art. It was
disbanded in 1771, reestablished in 1783, and suppressed again in
- This on-again off-again pattern reflected personal and doctrinal
disputes within the French army that characterized the entire period
between the end of the Seven Years War and the outbreak of the
Revolution twenty-six years later.
Such an atmosphere proved fertile in other directions as well. High
command, relying on maps and written orders prepared in advance by
specially trained staff officers, could perhaps hope to control armies
three or four times the size that Maurice de Saxe had judged to be the
upper limit of effective command; but to do so a general needed to
break his army up into parts, since existing roads and lines of supply
could not possibly accommodate scores of thousands of men. Parallel
lines of march undertaken by self-sufficient units that would be able to
defend themselves if they stumbled on an enemy along the route of
advance were what the situation required.
This was met by the invention of the division, i.e., of an army unit in - Use of contour lines to indicate slopes was a critical invention for making maps
useful to military commanders. Symbols for marshes and other obstacles to cross
country movement were also important but far easier to devise. Topographic contour
lines seem to have been first proposed in 1777 by a French lieutenant of engineers, J. B.
Meusnier; but use of lines to show water depths was far older, dating back among the
Dutch as far as 1584. Scarcity of data delayed resort to contour lines, which became
standard on small-scale maps only after about 1810 when improved surveying instru
ments made gathering data far easier and more rapid. Cf. François de Dainville, “From
the Depth to the Heights,” Surveying and Mapping 30 (1970): 389–403; Pierre Chal
min, “La querelle des Bleus et des Rouges dans l’artillerie française à la fin du XVIIIe
siècle,” Revue d'histoire économique et sociale 46 (1968): 481 ff. - Dallas D. Irvine, “The Origins of Capital Staffs," Journal of Modem History 10
( 1938): 166–68; Carrias, La pensée militaire française, pp. 176 ff.