The results furnished by the examination of the various samples 

 of Castilloa and Funtumia rubber so carefully and systematically 

 collected and prepared by Mr. Hart arc of considerable scientific interest 

 and are of obvious practical importance, especially in establishing the 

 conditions which must be secured in order to produce rubber of first 

 rate < quality. 



IV. — Sample ok Castilloa kubbeb prepared bi Weber's method. 



This sample of rubber of Castillo" elastica was forwarded to the 

 Imperial Institute by the Government, of Trinidad and is referred to in 

 a letter from the Colonial Secretary. No. yVj? dated May 8th, 1903. 

 The rubber had been prepared by the Superintendent of the Botanic 

 Department according to the method suggested by Dr. C. O. Weber, 

 which consists in the addition of formaldehyde to the creamed latex. 

 The following particulars were supplied regarding the exact procedure 

 adopted : — 



" Latex from Castilloa trees 14 to 16 years old, 500 c.c. creamed 

 in four times its volume of clean water, three times in succession to 

 remove albuminoids. Added 20 c c. of commercial formalin to latex 

 when creamed on last lot of water. No cohesion took place until 96 

 hours after mixing. Rubber then lifted and pressed. Cold water 

 was used." 



The specimen was a semicircular cake, -t inches in diameter and 1 

 inch in thickness, which weighed about 50 grams. Externally it was a 

 light brown colour but within it was quite white, perfectly dry and free 

 from foreign matter. The rubber exhibited very satisfactory physical 

 properties ; it was not sticky and was very elastic and tenacious. 



The following results were obtained on chemical examination : — 



Calculated for 

 dry material. 



91-2 



8-2 

 0-6 

 l>"2!> 



These figures are practically identical with those furnished by 

 sample No. 12 of the previous consigment, which was prepared by 

 coagulating the wash and creamed latex by alcohol. The physical 

 characters of the two specimens were also very similar, the only 

 difference being that the samples prepared by Weber's method was 

 much lighter in colour. 



The brokers also regarded the two specimens as of equal value 

 and quoted for each a price of 2s. 9d. per pound. 



WYNDHAM li. DUNSTAN. 



10th November. 1900. 



