Gums, Resins, 



10 



[Jan. 1907. 



Figgis & Sons, and Messrs. Lewis & Peat. As in the case of the physical properties 

 of rubber, this comparison affords no very definite principles, and it is at present 

 more or less a mere record of facts which may be of use in the future. 



Visitors to the Exhibition will remember that the exhibits included three 

 cases of rubber from America, Africa, and Asia respectively. These have been 

 compared with samples of Plantation rubber, (4) exposed during the Exhibition 

 and afterwards to the end of the year, and (5) exposed during the Exhibition 

 and subsequently enclosed in a museum case. Two sources of error may be pointed 

 out ; (a) the Ceylon rubber is the more recently manufactured and presumably 

 more liable to become mouldy ; (b) the foreign rubbers may have passed through 

 a mouldy period before their arrival in England. The first may be granted as 

 a point in favour of the foreign rubbers ; but the second is, I think, invalid, since 

 the samples are in most cases only sections of larger lumps, and these were cut 

 in England, thus exposing a surface not previously subjected to the action of 

 moulds. Moreover, the mould is the same in all instances, and is a Ceylon species, 

 not an English one. 



In explanation of the tables, it nmst be stated that "irregular lumps" 

 means small lumps welded into large masses with numerous interspaces, and 

 " traces " (of moulds) indicates an amount and kind which would not be discerned 

 by any one but a mycologist. This apparently rash statement will be 

 explained later. 



I. South and Central America. 



Hard cure fine Para 

 Para negroheads 

 Manaos scrap 



Peruvian and Upper Amazon 



ball 

 Peruvian slab 



Matto Grosso virgin 



Matto Grosso negrohead 

 Manicoba Plantation sheet ... 



Manicoba scrap 



Assare scrap 



Santos Mangabeira 

 Nicaraguan scrap 

 Carthagena scrap 

 Columbia virgin scrap 

 Mexican Plantation Castilloa 



Nov. 12. 00. 



slightly 

 mouldy 

 traces 



traces 



very badly 

 the first to 

 mouldy 



mouldy 



traces 



appears to 

 have been 



mouldy 

 previous 

 to arrival 

 in Ceylon 

 but 



cleaned 



Dec. 29. 06. 



very 

 mouldy 

 mouldy 



traces 

 traces 



slightly 

 mouldy 

 slightly 

 mouldy 



traces 

 mouldy 



become 



slightly 



very 

 mouldy 

 traces 

 mouldy 



irregular lumps containing 

 earth 



irregular wound sheet: much 

 bark 



large spongy lumps 



large, partly homogeneous 

 lump 



large irregular lumps : bark 



irregularly wound sheet: much 

 bark 



much bark and earth 



homogeneous lumps 

 compressed, very barky, scrap 



»l !> >> >> 



compressed, barky sheets 

 biscuits 



