The winter of 1812-13 was exceeding cold in November, December and January. It was this unusually early and bitter winter which occasioned the destruction of Napoleon's army in Russia, and the eventual overthrow of his power. (For no one who considers his achievements during the campaigns of 1813 and 1814 can doubt that, had the army with which he invaded Russia been at his command, he would have foiled all the efforts of combined Europe against him.) The cold became very intense in Russia after the 7th of November. On the 17th the thermometer fell to 15 degrees below zero, according to Larrey, who carried a thermometer suspended from his button hole. The retreat from Moscow began on the 18th, Napoleon leaving the still burning city on the 19th, and the evacuation being complete on the 23rd. Everything seemed to conspire against Napoleon and his army. During the march to Smolensk snow fell almost incessantly. Even the only intermission of the cold during the retreat caused additional disaster. On the 18th of November, Russian troops had crossed the frozen Dwina with their artillery. A thaw begun on the 24th, but continued only for a short time; 'so that from the 26th to the 29th the Beresina contained numerous blocks of ice, but yet was not so frozen over as to afford a passage to the French troops.' It was to this circumstance that the terribly disastrous nature of the passage of the Beresina must mainly be attributed. The winter of 1813-14 was colder in England than on the Continent--I mean, the winter here was colder for England than the winter in any region of continental Europe was for that region. The frost lasted from December 26 to March 21, and the mean temperature of January was only 26.8 degrees. The Thames was frozen over very thickly, and a fair was held on the frozen river.