33 



ments of bark and wood of rather large size which on removal were 

 found to amount to 4*6 per cent, of the total weight. The rubber wan 

 very elastic and tenacious, and only slightly sticky. 



\n. 12. — Castilloa. 



'" Specimen of rubber made from washed and creamed latex ol 

 trees 12 years old and over. Coagulated with alcohol. This appears 

 to be the liest specimen of Castilloa sent." 



The sample was ;i small piece of black rubber weighing 'A7 grams : 

 internally it was a dark greyish colour throughout, dry. and quite 

 free from foreign matter. The physical characters of the rubber were 

 very satisfactory : it exhibited considerable elasticity and tenacity, and 

 was not sticky. In appearance and characters it was certainly the best 

 specimen of Castilloa rubber submitted. 



Chemical Examination. 



The following results were obtained on analysis of the various 

 samples : — 



SAMPLES AS RECEIVED. 



It will be seen from these figures that the three specimens of 

 Castilloa rubber. Nos. 3, 4, and 7, which were obtained from trees 4J 

 years old, contain very large amounts of resin, viz: 52'6, 56*2 and 49*3 

 per cent, respectively on the dry material, and they would therefore 

 possess little value as rubbers. The results of the chemical examination 

 confirm the opinion based upon the physical characters of the specimens 

 and it is clear from these results that Castilloa trees 4| years old will 

 not yield a marketable rubber. This conclusion agrees with that 

 arrived at by previous investigators but it must be remarked that the 

 amount of resin present in the specimens under notice, and also in the 



* These specimens were air-dried before analysis. 



t Exclusive of 4 "6 per cent, of bark removed before analysis. 



