“ Luzon, like all of the East India islands, is exceedingly well watered. The largest river system of the island, as well as of the whole archipelago, is that of the Rio Grande de Cagayán, running north from Caraballo Sur, which is the principal watershed for the three largest rivers of the island, the other two being the Pampanga, running south into Manila Bay, and the Agno, flowing west into the Gulf of Lingayén. ”

“ Earthquakes are of frequent occurrence, and have on several occasions caused great losses of life and property, notably in 1863, when large parts of Manila were laid in ruins, and in 1880, when the whole island was convulsed with a series of severe shocks. The style of architecture has to be adapted to withstand these disturbances. ”

“ These do not differ materially from those of the other islands, and are described in the article Philippine Islands (q.v.) . Vegetation is everywhere extremely luxuriant, and large areas are covered with valuable forests. ”