topographical conditions of each place also exert great influence upon the amount of rainfall andthe force of the wind.

We called the rainfall of this season “cyclonic rainfall” rather than “monsoon rainfall,"because, the southwest winds which—generally speaking—bring most of it, are not true monsoonwinds. Moreover, the statement that they bring most of the rainfall of this season had to he qual-ified, since, strictly speaking, for each region within the area of the storm the winds'which bringthe heaviest rains are generally those which come from the nearest sea, irrespective of their direction.While the wind during the passage of a typhoon either veers or hacks through nearly 180 degrees ofthe compass, each place receives the rainfall principally when it blows from the most favorabledirection. Often the stations nearer to the center of a typhoon receive less rain, and even at timesnone at all, while others, farther from it, are flooded. The station of Aparri, for instance, on thenortheast coast of Luzon and the nearest to the general path of typhoons, has much less rainfall

than San Jose do Buenavista (Antique),'on the west coast of I’anay. The only cause which we are

able to assign for this fact is the topography of these places. Aparri has a .mountain range inthe western quadrants, hut San dose the open sea of Join.

Although it is true that the stations receiving more abundant rains are those exposed to the

southwest and west winds. Ibis does not prove that these winds are those of a real monsoon. 'They

prevail during the months Junc-Octobcr, because in those months frequent typhoons cross the north-cast and north of the Archipelago, giving rise to such winds. In the publications of this Observatoryit has always been claimed that the southwest winds prevailing in the Archipelago do not constitutea real monsoon—that is, winds dependent chiefly on the summer center of low pressure situated onthe Asiatic Continent—but that they are of cyclonic origin. This conclusion has been derivedfrom the fact that these soutlnvcsters cease almost completely as soon as the pressure reaches itsnormal height over that portion of the sea which runs from Japan to the east of .Mindanao,including Formosa and the .Philippine Archipelago, although the Asiatic center of low pressure mayremain without any apparent change. Thence the practical rule given by this Observatory: “Ifduring the months June, July, August, September, and October the southwest winds are blowingsteadily in the China, Join, and Mindoro. Seas, there is a cyclonic vortex situated in the north.” Itis not infrequent, especially during the month of August, 1 to have normal pressure with easterly andsoutherly winds blowing steadily over the whole Archipelago for long intervals; then the rains arescarce in the central and western regions (due only to local thunderstorms), and more abundant in theeastern. Sometimes, when the pressure rises above the normal the air currents back more to the north-east, become stronger, and produce heavy rains in the eastern and southeastern parts of the Archipelago,'this happens especially when the barometer, while remaining high in the north, falls a little in thesouthernmost part of Mindanao and over the Mindoro and Jolo Seas.

As to the distribution of the summer or cyclonic rainfall throughout the Archipelago, we mavsay it naturally decreases from west to east, or rather from northwest to southeast. In all therecords available we find only three stations with an amount of summer rainfall below JO per cent ofthe yearly normal; these are Surigao, Tandag, and Caraga. All the rest receive over JO per cent ofthe' annual amount, and none less than 480 millimeters. The stations reporting a quantity amountingto TO per cent or more of the annual rainfall are, with very few exceptions, those on the westerncoasts of Luzon, tlu 1 plains surrounding and extending northward from the Bay of Manila, in thehigh valley of Baguio, and on the western coasts of Mindoro and J’anay. The stations with 50 to 70per cent are those 1 of the plains of ('amarines, Luzon! the western and central Yisayas (to the onehundred and twenty-fourth meridian), and western Mindanao. With these also range Aparri, onthe northeast coast of Luzon ; Bayomhong, situated on a relatively high system of hills and vallevssurrounded by higher mountains; Maasin and Ormoe, on the western coasts of Leyte; and Calbayog,

1 See "(ii»m»rnl Woatlior Notes,” August.