334 STAECII-PRODUCING PLANTS. 



5. Guinea Yam (D. aculeata). Grown in the same locality. Larger globules, 

 elliptical ; smaller ditto, spherical, often truncated ; some shortly ovate, with 

 the appearance of being flattened; general size and range, same as No. 4. 



6. Barbados Yam, grown on banks of Domerara river. Globules, pear-shaped 

 and mullar-shaped ; range, 1-700 to 1-1,600; general size, 1-1,000. 



7. Plantain (Musa paradisiaca). Grown on the banks of the Demerara river. 

 Globules long and narrow, generally long elliptical, often more acute at the ends 

 than in any other species, some linear ended abruptly ; length, often three times 

 the width; range, from 1-400 to 1-4,000 of an inch; general size, 1-800. 



8. Potato (Solanum tuberosuni). Irish tubers, from Belfast Sound. Globules, 

 1-600 to 1-2,000 ; general size, 1-1,200. 



9. Potato (Commercial). Locality unknown. Range from 1-600 ; globules 

 generally same as former, but a few stray ones as large as 1-40 of an inch. 



10. Sweet Potato (Convolvulus Batatas}. Grown at the Lodge, Demerara. 

 Form of globules, spherical aggregated ; range, 1-1,000 to 1-4,000 ; general 

 size, 1-2,400. 



11. Arrowroot (Maranta arundinacea}. Specimens from Bermuda, where the 

 highest priced and best quality is prepared. Ovate and elliptical ; length in the 

 larger globules, twice the width ; range, from 1-800 to 1-2,400 ; general size, 

 1-1,400. 



12. Ditto ditto, grown on plantation Turkeyen, Demerara, by J. "W. King. 

 Size and description same as No. 11. 



13. Ditto ditto, grown and prepared in Barbados. Characteristics the same, 

 but globules more uniform in size. 



14. Ditto ditto, grown on plantation Enmore ; not quite so uniform in size. 



15. Bitter Cassava (Janipha Ma nth of). Grown on Haagsbosch plantation. 

 A few globules occur as large as the 1-1,000 of an inch; these are ovate, the 

 rest are spherical. The range is from 1-2,000 to 1-8,000 ; general size, 1-4,000. 



16. Sweet Cassava (Janipha Loeftingii}. Grown on No. 1 Canal, Demerara 

 River. 



17. Tannia (Caladium sagitti folium} . Grown at the Lodge. Globules not so 

 truly spherical as the foregoing, but range and size the same. 



18. Wheat (Triticum sativuni). Locality unknown. Form of globules, spher- 

 ical and slightly elliptical, some very small ; range, 1-2^000 to 1-6,000, the 

 former the general size. 



19. Maize (ZeaMays). Grown in the colony, but locality uncertain. Globules, 

 approaching to spherical, much aggregated; range, 1-2,000 to 1-4,000; general 

 size, 1-3,000. 



From an inspection of this list, it does not appear that the 

 species would be easily distinguishable, and it is not easy briefly 

 to describe the differences ; in practice, however, and especially 

 when the observer has a number of pure and authentic specimens 

 before him, to have recourse to as standards of comparison, the 

 discrimination is by no means difficult. 



Specific gravity of starch derived from various plants. Of 

 many bodies the determination of the specific gravity is one of the 

 best modes of distinguishing the purity. With the view of ascer- 

 taining whether the different varieties of starch have all the same 

 density, as has been asserted by some, trials were carefully made 

 of as many specimens as I could procure. The results are em- 

 bodied in the following table : 



