December, 1908.] 



£09 



Saps and Exudations. 



No. 15. " Castilloa block from trees 

 17 years old." Weight 2£ lb. 



An oblong piece of rubber, about 2 feet 

 long, from 3 to 4 inches wide and 1 inch 

 thick. 



The rubber was brown externally but 

 lighter within ; it was clean, free from 

 stickiness, and exhibited fair elasticity 

 and tenacity. 



The following results were obtained 

 on analysis :— 



Rubber as Composition 

 received. of dry rubber. 





Per cent. 



Per cent. 



Moisture 



0-8 





Caoutchouc 



69-2 



752 



Resin 



. 212 



23 



Proteids 



0-6 



0-7 



Insoluble matter .. 



ro 



11 



Ash 



1-99 



2-15 



This sample of Castilloa rubber is of 

 better quality than Nos. 10 and 11, but 

 the amount of resin is still excessive. It 

 was valued at 3s. 6d. per lb. in Loudon. 

 The scrap rubber from the same soui'ce 

 sample No. 16, was valued at 2s. Id. per lb. 



No. 17. "Castilloa sheet." Weight lib. 



A. large sheet of rubber 12 x 14 inches, 

 and from 1/16 to | inch thick. 



The rubber was clean, pale yellow, 

 and free from stickiness ; it was, how- 

 ever, weak and tore readily. 



The rubber had the following com- 

 position :— 



Rubber as Composition 

 received, of dry rubber. 





Per cent. 



Per cent. 



Moisture 



... 8-0 





Caoutchouc 



... 76-1 



76'7 



Resin 



.. 21-5 



21-7 



Proteids 



,.. 0-5 



0"5 



Insoluble matter 



... l'l 



1-1 



Ash 



... 0-71 



0-72 



This sample is very similar in composi- 

 tion to No. 15, but is a little weaker. It 

 was valued at 3s. 5d. per lb. in London. 

 The corresponding scrap rubber was 

 valued at 3s. per lb. 



No. 19. "Castilloa sheet." Weight 

 5£ oz 



Two thin sheets of clean rubber, pale 

 colour, sticky. The rubber was very 

 weak and tore readily. 



The following results were obtained 

 on analysis :— 



Per cent. 



Moisture ... ... 0"1 



Caoutchouc ... ... 60'9 



Resin ... ... 37'2 



Proteids ... ... 0'1 



Insoluble matter ... ... 1*4 



Ash ... ... 0-37 



This sample is of inferior quality on 

 account of the high percentage of resin. 

 In composition it agrees well with 

 sample No. 11, The scrap rubber, No. 

 20, contained a little less resin than the 

 sheet, viz., 324 per cent. The sheet 

 rubber was valued at 2s. 3d. per lb., 

 and the corresponding scrap rubber in 

 ball form at 3s. per lb. in London. 



No. 21. " Castilloa sheet." Weight 5 oz. 



Three small irregular cakes of clean 

 black rubber, which exhibited fair elas- 

 ticity and tenacity, but tore when 

 stretched. 



The rubber had the following com- 

 position : — 



Rubber as Composition of 



received. dry rubber. 



Per cent. Per cent. 



Moisture ... 1*0 — 



Caoutchouc 75-4 76-1 



Resin ... 20-4 20'6 



Proteids ... 0*6 0-6 



Insoluble matter 2*6 2*7 



Ash ... ... 2-17 2-19 



This sample corresponds in compo- 

 sition and quality with Nos. 15 and 17. 

 It was valued at 3s. 6d. per lb. in London. 



No. 22. " Castilloa sheet." Weight 15 oz. 



Two thin sheets of rubber about 10 

 inches square. The rubber was clean, 

 well prepared, pale in colour and free 

 from stickiness ; it exhibited good elasti- 

 city and tenacity, being much superior 

 in these respects to all the other samples. 



The results of the analysis were as 

 follows : — 



Per cent. 



Moisture ... ... 0'1 



Caoutchouc ... ... 83*0 



Resin ... ... ... 15'6 



Proteids ... ... 0*4 



Insoluble matter ... ... 0'9 



Ash ... ... ... 0-51 



This sample of Castilloa rubber con- 

 tains less resin than any of the other 

 specimens. It was very well prepared 

 and is certainly the best sample of 

 Castilloa rubber in the series. It was 



