TESTS OP PHILIPPINE ROAD MATERIALS. 459 



As soon as the abrasion machine was constructed, the Sisiman rock 

 was tested and its percentage of water was found to be 4.08. This test 

 demonstrated much more economicall}^ the unsuitability of the rock than 

 did the practical test, and showed the value of using the abrasion machine. 



In looking for a c[uarry site, the shores of the Bay Lalce (Laguna de 

 Bay) and Manila Bay were carefully explored as well as all points from 

 which railway transportation appeared feasible. It was- soon discovered 

 that it would be impossible to ship stone by rail at the present freight 

 rate, or even at such reduced rates as the company might be willing to 

 concede, since the railway rates are high and seemingly excessive. No 

 good quarry site was found on the immediate shore of the lake. The 

 occurrence of hard rock on the shores of Manila Bay are all near the 

 entrance, and most of them at places where the conditions for quarrying 

 and loading are not favorable. Transportation across the bay could not 

 be depended upon during rough weather, and this would be a serious 

 handicap to the city since continuous operations are necessary in order 

 to supply the amount of stone required, and if the launches and lighters 

 and employees were unable to carry on continually this work they 

 could not be employed readily in other duties. 



The railroad to Antipole passes an extensive outcrop of basalt in the 

 vicinity of Antipolo Falls which is to the north of Binangonan Peninsula 

 in the same zone of basaltic rocks. Samples of this stone were collected 

 and tested for the sake of information. They showed 2.61 per cent of 

 wear, or practically the same amount as the best grade of Talim rock; 

 and although the fracture of this stone was somewhat better than that 

 at the Talim quarry, it appeared that little could be gained by using it, 

 and transportation, which would necessarily be by rail, would be too 

 expensive. Between Antipolo and Taytay, in making a cut, a very hard 

 stone was found and the railroad company called the attention of the 

 division of mines to its occurrence. It was examined in the field and 

 the exposures were found unsuitable for establishing a quarry. The 

 rock was not tested, although a sample of it was obtained. Similarly, 

 the limestone at the waterworks dam near Montalban was examined, 

 since it was suggested that it might show better cementing values, and, 

 being an unusually hard limestone, might prove suitable for macadam. 

 The percentage of wear of this stone was found to be 3.97 per cent. 

 Although it is superior limestone, it is not good enough to recommend 

 for use on city streets ; moreover, the color, which is nearly white, would 

 be a serious disadvantage because of the strong reflection of light from it. 



Up to this point in the field work, investigations had been carried on 

 with the hope of satisfying the desire of the city ofBcials to be informed 

 of a location which would necessitate only water transiDortation. It 

 was ascertained that a good quality of the rock could not be found 

 situated imder these conditions. It was believed that the hard stone 



