322 The Philippine Journal of Science i9i« 



for the most resilient coir filament. This high resilience and 

 elasticity, coupled with its extraordinary tensile strength, are 

 the chief factors in accounting for the fact that abaca is con- 

 sidered the premier cordage fiber of the world. 



A COMPARISON OF THE MECHANICAL PROPERTIES O^ COIR AND 

 ABACA (MANILA HEMP) ROPES 



Three handmade, three-strand coir ropes of different sizes 

 were tested. Two of these made of coir from Laguna husks, 

 machine-cleaned at the Bureau of Science, had circumferences 

 of 24 and 44 millimeters, respectively. The other Was a retted 

 coir rope 50 millimeters in circumference obtained from Caoayan, 

 Ilocos Sur. The machine-cleaned fiber was spun by hand into 

 strands at the Bureau of Science, and the Bureau of Agriculture 

 had the spun fiber laid into two ropes at a Pasig ropewalk. The 

 rope had the ragged, rough appearance, due to the numerous 

 protruding filament ends, that is characteristic of untrimmed 

 coir rope, whether hand or machine laid. 



The abaca specimens consisted of four sizes of Government 

 inspected, pure "F" and "G" grades, three-strand rope, 15, 16, 

 26, and 31 millimeters in circumference, respectively. The ropes 

 were machine laid with about 10 per cent of mineral oil added 

 to the fiber during manufacture for lubricating purposes, and for 

 its ultimate preservation. The test specimens of both abaca and 

 coir were prepared with eye-splices at the ends. The distance 

 between splices was either 50 or 100 centimeters as shown in 

 each case in the table. Each eye and splice measured about 15 

 centimeters in length. Three tucks were made in each splice, 

 and the internal diameter of the eyes was 4.5 centimeters. 



Circumference and diameter. — The measurements of the aver- 

 age actual girth, or perimeter, of the ropes given in Tables XI, 

 XII, XIII, and XIV were obtained by encircling each test speci- 

 men with a strip of tough linen paper about 2 millimeters wide 

 and marking it with a very sharp pencil at a convenient over- 

 lapping point. The strip was then straightened and measured on 

 a scale graduated in millimeters. As the irregular nature of the 

 cordage introduced appreciable variation in size, the readings 

 were taken to the nearest whole millimeter. The girth obtained 

 in this manner is less than the internal circumference of a ring 

 through which the specimen will just pass ; but numerous meas- 

 urements show that for small ropes the difference is so slight 

 that the gii-th has been considered adequately approximate to 

 the true circumference of the rope. 



