6o6 TEE POPULAR SCIENCE MONTHLY 



an army to proceed on its plan of advance, and, on the other hand, the 

 ice may help a pursuing army to follow its retreating enemy without the 

 delay needed for building bridges. In 1780, troops were led on the ice 

 from New Jersey to Staten Island, to attack the British, and provisions 

 were sent across on sleighs. In 1809, the Eussians were led to Sweden 

 across the frozen Gulf of Bothnia. Sudden thaws after severe cold are 

 often serious handicaps in a campaign. Boads and fields are suddenly 

 turned from hard ground into deep mud or swamp, and the movement 

 of troops, and especially of guns and supplies, may be stopped. Heat 

 has caused as great suffering as has the cold, but less often, in our 

 latitudes. The sufferings of the French army under General Kleber in 

 Egypt in 1798 are well known to students of history. Officers threw 

 themselves on the sand and gave way to despair. 



If we look over the foregoing, and many other cases of weather 

 controls in war, it is easy to see that these examples may be grouped in 

 two classes. In one of these, the particular weather condition or phe- 

 nomenon was so to speak accidental ; it was sudden ; unexpected at that 

 special time ; and therefore hardly to be guarded against. Cases of this 

 sort are the sudden storms which have so often been decisive facton in 

 military undertakings. In the second class the weather conditions 

 were perfectly normal and natural for the particular region and sea- 

 son in which they occurred, but the army was not prepared for them 

 because of the ignorance, or lack of foresight, or over-confidence, or 

 haste, on the part of the commanding officers. Thus, the terrible dis- 

 aster which befell the French army in Russia was largely due to Na- 

 poleon's own recklessness in rushing unprepared troops into the teeth 

 of a northern winter. Cold and snow contributed towards making a dis- 

 aster complete which would probably have been a serious one under any 

 meteorological conditions. Again, during the British expedition into 

 Tibet, a few years ago, great difficulty was experienced at the higher 

 altitudes owing to the hardening of the oil in the guns, on account of 

 the cold, and the low boiling point at those great altitudes made it 

 difficult to cook food properly in the absence of special cooking utensils 

 adapted for use at low pressures. These handicaps could have been 

 provided against if proper care had been taken beforehand. 



It is clear that weather, although not always, or ultimately, is a 

 factor which must be reckoned with in warfare. It is one of a large 

 number of factors, among which topography, soil, hydrography, vegeta- 

 tion, and so on, must also be included. To know, in advance, the gen- 

 eral climate of the war zone; to be prepared for the special weather 

 conditions which are reasonably to be expected at this or that season; 

 to have as accurate a knowledge as possible of the probability of occur- 

 rence of severe cold; of sudden thaws; of heavy rains; of great heat; 

 of high winds ; of deep snows — this is a very essential element in plan- 



