The flow- and ebb-tides, and the high and low tides among these islands are so diverse in them that they have no fixed rule, either because of the powerful currents among these islands, or by some other natural secret of the flux and reflux which the moon causes. No definite knowledge has been arrived at in this regard, for although the tides are highest during the opposition of the moon, and are higher in the month of March than throughout the rest of the year, there is so great variation in the daily tides that it causes surprise. Some days there are two equal tides between day and night, while other days there is but one. At other times the flow during the day is low, and that of the night greater. They usually have no fixed hour, for it may happen to be high-tide one day at noon, while next day high-tide may be anticipated or postponed many hours. Or the tide of one day may be low, and when a smaller one is expected for next day, it may be much greater. The language of all the Pintados and Bicayas is one and the same, by which they understand one another when talking, or when writing with the letters and characters of their own which they possess. These resemble those of the Arabs. The common manner of writing among the natives is on leaves of trees, and on bamboo bark. Throughout the islands the bamboo is abundant; it has huge and misshapen joints, and lower part is a very thick and solid tree. [134] The language of Luzon and those islands in its vicinity differs widely from that of the Bicayas. [135] The language of the island of Luzon is not uniform, for the Cagayans have one language and the Ylocos another. The Zambales have their own particular language, while the Pampangos also have one different from the others. The inhabitants of the province of Manila, the Tagals, have their own language, which is very rich and copious. By means of it one can express elegantly whatever he wishes, and in many modes and manners. It is not difficult, either to learn or to pronounce. The natives throughout the islands can write excellently with certain characters, almost like the Greek or Arabic. These characters are fifteen in all. Three are vowels, which are used as are our five. The consonants number twelve, and each and all of them combine with certain dots or commas, and so signify whatever one wishes to write, as fluently and easily as is done with our Spanish alphabet. The method of writing was on bamboo, but is now on paper, commencing the lines at the right and running to the left, in the Arabic fashion. Almost all the natives, both men and women, write in this language. There are very few who do not write it excellently and correctly. This language of the province of Manila [_i.e._, the Tagal] extends throughout the province of Camarines, and other islands not contiguous to Luzon. There is but little difference in that spoken in the various districts, except that it is spoken more elegantly in some provinces than in others. [136]