This conclusion is further justified by the language in which a large per cent of the words in daily use are common to all the groups. Even the Bila-an dialect, which differs more from all the others than do any of those from one another, has so many words in common with the coast tongues and is so similar in structure that one of my native boys, who never before had seen a Bila-an, was able freely to carry on a conversation within a few days after his arrival in one of their most isolated settlements. Similar as are the people and their dialects, the cultural agreements are even more noticeable. Taking the Bagobo as a starting point, we find a highly developed culture which, with a few minor changes, holds good for the tribes immediately surrounding. These in turn differ little from their neighbors, although from time to time some new forms appear. The Cibolan type of dwelling, with its raised platform at one end and box-like enclosures along the side walls, is met with until the Mandaya territory is approached, while, with little variation, the house furnishings and utensils in daily use are the same throughout the District. The same complicated method of overtying, dyeing, and weaving of hemp employed in the manufacture of women's skirts is in use from Cateel in the north to Sarangani Bay in the south, while in the manufacture of weapons the iron worker in Cibolan differs not at all from his fellow-craftsman among the Mandaya. Here we are confronted by the objection that, so far as is known, no iron work is done by the Bila-an and Ata, but this is a condition which is encountered throughout the archipelago. In the interior of Luzon are found isolated villages, the inhabitants of which are expert workers in iron and steel, while their neighbors seem to be ignorant of the process.[142] The writer holds to the opinion that iron working is an ancient art throughout the Philippine archipelago and that its use for various reasons, such as lack of material, has died out in certain sections. Brass workers are found among most of the tribes, but, as was observed earlier in this paper, there is sufficient evidence that the industry is of recent introduction, and the amount and excellence of the work done by the brass casters is governed by the nearness or remoteness of Moro settlements. [142] The process used in Northern Luzon is very similar to that employed in Southern Mindanao. Except for the cotton garments recently adopted by the Kagan branch of the Tagakaolo, and the suits worn by the Mandaya men, the clothing seen throughout the District is very similar. A few ornaments, such as the silver rings and breast disks of the Mandaya, have only a limited distribution, but for the most part the decorations worn by the different tribes differ only in the number of beads, bells, and shell disks used in their manufacture.