382 The Philippine Journal of Science i9i5 



or larger than the size used by the Filipinos in determining the 

 strength of the brine. There are very few Filipinos who use a 

 specific gravity spindle or a salometer to determine the strength 

 of the brine. 



The leaching vat commonly used in Rizal and Cavite Provinces 

 consists of a circular dike about 50 centimeters high and 4 meters 

 in diameter, which is built on the ground. The bottom is covered 

 with a layer of palm leaves, usually nipa, and rice husks, which 

 filter the mud from the brine. By means of bamboo piping the 

 filtered brine is drawn off through the dike into a shallow 

 cement, earthenware (pilon), or clay-lined well. Dilute brine 

 is dipped back into a leach, and the operation is repeated, until 

 it becomes strong, when it is transferred to shallow crystallizing 

 ponds. 



After the leached mud has hardened slightly, it is marked 

 off into squares. While the leaching is in progress, another 

 layer of loose earth is being impregnated. This is scraped into 

 heaps about the leach, while the squares of leached mud are 

 drying. When the blocks have sufficiently hardened, they are 

 thrown from the leach back on to the field. After the second 

 crop of salty earth has been scraped into the leach, the clods are 

 pulverized and carefully spread out again to be impregnated. 



The crystallizing ponds are floored with smooth, broken 

 pottery (tinajas or pilones) set in lime mortar to retard seepage 

 and to prevent the admixture of sand with salt. The ponds are 

 surrounded with bamboo fences covered with nipa or cogon 

 grass in order to prevent the prevailing wind from blowing dust 

 into them and the floating crystals from congregating on the 

 leeward side. As the crystallizing ponds require more liquid, 

 more and more of the strongest brine is added. It is poured 

 through a straw-filled, open-work basket filter to remove rice 

 husks, which may have gotten in from the leach, and especially 

 to prevent disturbance of the bottom of the pond. When the 

 brine is sufficiently concentrated to deposit salt, every day after 

 sundown, when the temperature has fallen, to give the maximum 

 crystallization, the crystals are raked into heaps at the side 

 of the vats, gathered into baskets to drain, and finally conveyed 

 into warehouses. 



MODIFICATIONS OF IRAS TAGALOG METHOD 



The iras Tagalog method is more or less modified in other 

 parts of the Archipelago, but the principle of the process remains 

 the same. In Antique, Cebu, Iloilo, Negros, and Palawan Prov- 

 inces beds of bamboo split in half serve as crystallizing ponds. 



