xiu. A, 6 King: Philippine Coir and Coir Cordage 295 



the pan, P, falls. In these tests the valve was adjusted to the 

 smallest working aperture, so that the shot issued at the lowest 

 average rate, 33 grams per second. 



Technic of testing. — In testing a filament the exposed length 

 was adjusted to 100 millimeters as shown on the scale, the spe- 

 cimen previously having been cut to a length of 150 millimeters to 

 provide 25 millimeters to be clamped firmly in each grip. Care 

 must be exercised that the filament will not slip in the grips. 

 Grips made of metal mash the filament, causing rupture in the 

 jaws; in order to prevent such injury the jaws were lined with 

 Bristol board. The final step before beginning the test was the 

 careful adjustment of the shot pan suspended on a hook on the 

 lower grip. While one operator started the flow of shot by 

 pushing up on the yoke to which the valve is fastened, another 

 snapped a stop watch the instant the valve opened. The first 

 operator, sighting at right angles to the length of the specimen 

 over the upper end of the descending lower grip, called aloud 

 the graduations of the scale at the instant they were uncovered, 

 and the second operator simultaneously recorded the corre- 

 sponding number of seconds in a table previously prepared in 

 blank. The elongation was read at 1-millimeter intervals. 

 When the filament broke, the loaded shot pan fell on the trigger, 

 thus instantaneously closing the valve, and at the same instant 

 the watch was stopped. The duration of the test and the weight 

 of the shot and pan were recorded. From these data the ten- 

 sile strength, elongation, and elasticity of the filaments were 

 calculated. For the purpose of comparison, similar tests were 

 performed upon abaca (Manila hemp) filaments. Since there 

 are no bearings, knife edges, or other points of contact in the 

 device that might cause friction and so affect the results, the 

 values obtained are probably more accurate than could be se- 

 cured with most testing machines on the market. 



Tensile strength. — Tables III and IV give the results of tests 

 made on the tensile strength of machine-cleaned and retted coir 

 filaments, respectively, and Table V gives results of tests with 

 abaca filaments. 



The results show that the machine-cleaned coir filaments from 

 Laguna are considerably stronger than the retted filaments from 

 Ilocos Sur. However, when compared with grade "F" abaca 

 filaments, which are standard for cordage manufacture, the low 

 tensile strength of coir is evident. Whereas the maximum ten- 

 sile strength of coir is only 1,546 kilograms per square centi- 

 meter, abaca shows a tensile strength of 8,570 kilograms per 



