ON BITTER CASSAVA. 107 



of oil, lamp-black, rosin, and other ingredients, boiled together till about 

 the consistency of melted tar. From between the cylinders, dressed in its 

 black coat, the cloth is carried to the story above through an aperture in 

 the floor, and wound iipon a huge wooden frame, resembling in shape the 

 old-fashioned reel. By an arrangement of spokes upon the arms of this 

 huge wheel, each layer of cloth is kept separate, so that no two portions of 

 the cloth will come in contact. The frame, with its contents, when filled, 

 is passed into what is called the heater, an apartment kept at a high 

 temperature, for the purpose of drying in the coating of composition. 

 After remaining in the heater a sufficient time to complete the drying 

 process, it is removed to the lower story, whence it originally started, to 

 pass through the hands of workmen, who make all the rough places 

 smooth. It is laid on long tables, and alternately sprinkled with water 

 and rubbed with pumice-stone till the whole surface is made perfectly 

 smooth. The cloth is then wound upon the cylinder again, as at first, and 

 passed through the machine into the upper story, upon the huge reels, and 

 into the heater, and again under the pumice-stone. The cloth is passed 

 through the machine five times, or till the required thickness has been 

 laid on. After the last scrubbing clown, the fabric is taken to another 

 department in the upper story, thoroughly varnished, and again passed 

 through the heater. It is now a piece of cotton cloth, with a thick shining 

 coat of black, very much resembling patent leather. But it has not yet 

 received its leather finish ; so, in another department, it is passed through 

 the enamel machine, which consists of another set of huge rollers, one of 

 which covers its surface with irregular indentations, resembling the grain 

 of leather. 



ON BITTER CASSAVA (MANIHOT UTILISSIMA). 



BY LOUIS HOFFMAN, ISLAND CHEMIST OF JAMAICA. 



The starch from this root is of such superior quality, its preparation so 

 simple, and the juice of the root so valuable as an antiseptic, that it certainly 

 deserves a high rank amongst our agricultural productions. The series of 

 experiments which I have begun on this root have for their object the 

 preparation from it of a substitute for wheaten flour, fit, of course, for the 

 manufacture of good wholesome baker's bread. The results I have already 

 obtained are very encouraging, and shall form the subject of a future 

 article. 



Most of the starch-bearing roots are very similar in their composition, 

 and do not differ to any very great amount in the per-centage of starch 

 which they contain ; and even the amount of starch produced per acre of 

 soil by the different root-crops does not vary to any enormous extent. 

 Potatoes, for instance, yield about two and a* half tons of starch per acre, 



