Problem: I know that the answer to the question "Appomattox lost a quarter of __" is in "Davis and his cabinet left the city by train that night, as government officials burned documents and departing Confederate troops burned tobacco and other warehouses to deny their contents to the victors. On April 2, 1865, General Godfrey Weitzel, commander of the 25th corps of the United States Colored Troops, accepted the city's surrender from the mayor and group of leading citizens who remained. The Union troops eventually managed to stop the raging fires but about 25% of the city's buildings were destroyed-". Can you tell me what it is?

A: city's buildings


Problem: I know that the answer to the question "How would you travel to the reservoir from the plant?" is in "The Zipingpu Hydropower Plant (simplified Chinese: 紫坪铺水库; traditional Chinese: 紫坪鋪水庫) located 20 km east of the epicenter was damaged. A recent inspection indicated that the damage was less severe than initially feared, and it remains structurally stable and safe. The Tulong reservoir upstream is in danger of collapse. About 2,000 troops have been allocated to Zipingpu, trying to release the pressure through spillway. In total, 391 dams, most of them small, were reported damaged by the quake.". Can you tell me what it is?

A: upstream


Problem: I know that the answer to the question "Which of the following is not a trait of paraffin wax: inexpensive, high specific heat capacity, or readily available?" is in "Phase change materials such as paraffin wax and Glauber's salt are another thermal storage media. These materials are inexpensive, readily available, and can deliver domestically useful temperatures (approximately 64 °C or 147 °F). The "Dover House" (in Dover, Massachusetts) was the first to use a Glauber's salt heating system, in 1948. Solar energy can also be stored at high temperatures using molten salts. Salts are an effective storage medium because they are low-cost, have a high specific heat capacity and can deliver heat at temperatures compatible with conventional power systems. The Solar Two used this method of energy storage, allowing it to store 1.44 terajoules (400,000 kWh) in its 68 cubic metres storage tank with an annual storage efficiency of about 99%.". Can you tell me what it is?

A: high specific heat capacity


Problem: I know that the answer to the question "what period in time is mentioned first?" is in "In 1808, Napoleon and Czar Alexander met at the Congress of Erfurt to preserve the Russo-French alliance. The leaders had a friendly personal relationship after their first meeting at Tilsit in 1807. By 1811, however, tensions had increased and Alexander was under pressure from the Russian nobility to break off the alliance. A major strain on the relationship between the two nations became the regular violations of the Continental System by the Russians, which led Napoleon to threaten Alexander with serious consequences if he formed an alliance with Britain.". Can you tell me what it is?

A:
1808