ON THE COMMERCIAL KINDS OF INDIA-RUBBER. EL 
On another specimen, collected by Dr. Spruce in Ecuador, in De- 
cember, 1860, are the words, “ The India-rubber Tree of Guay aquil.” 
Of the different commercial kinds of india-rubber furnished by Cas- 
tilloa elastica, Cerv., we may mention :—1. West India (so- called) ; 
2. Carthagena ; 3. Honiara 4. Guayaquil; and 5. Guatemala ;—all 
named after the places whence shipped. Indeed, they are so very much 
alike in character, that a merchant dealing largely in them told me 
that they were all the same,—the different amount of careful treatment 
they received resulting in the improved look of the better kinds. 
West India rubber is not, in most instances, the produce of any of 
the West India islands, but is named so from the mail steamers calling 
at St. Thomas on their way home. The best is pressed into thin clean 
sheets, devoid of the excessive moisture and “ tarry ” look perceivable 
in the lower kinds. It is a black-looking india-rubber in appearance. 
The quantity brought to England by the West India mail steamers 
very seldom exceeds 15 tons a month, the usual quantity being from 
3 to 6 tons. It is much valued, I believe, on the Continent. 
Carthagena india-rubber is imported in the form of sheets about 
three-quarters of an inch thick, and can always be distinguished from 
the other kinds by having a peculiar chewed appearance externally, 
most probably arising from the pressure used in driving off the mois- 
ture. ls. 7d. to ls. 8d. is about the average price. By skilful treat- 
ment this rubber has been used for many purposes for which Para 
alone could formerly be used. Formerly it was 8d. to 1s. 2d. cheaper 
than Para; now there is only about 6d. difference. It is black, tough, 
and occasionally “ tarry” in appearance. 
Honduras india-rubber has a greenish-grey appearance when cut, 
the exterior being dark. It is firm in texture, and not porous. Its 
price is 1s. 5d. to 1s. 6d. per Ib. 
Guayaquil india-rubber comes over in large black flakes or lumps. 
When cut, it is sometimes whitish, but in the lower kinds very porous, 
the pores being filled with a black liquid, which stains the hands and 
knife, leaving a disagreeable odour behind. Sometimes, by the mere 
pressure of the hand, a large quantity will exude. Its price is from 
Is. 3d. to 1s. 4d. 
Guatemala india-rubber is the worst kind. It is in large blocks, 
consisting of thin sheets pressed together. From between the sheets, 
when fresh, a black resinous thick fluid exudes. After a time this 
