Vol. XI. No. 256. 



'^ THE AGRICULTURAL NEWS. 



61 



STUDENTS' CORNER. 



AGRICULTURAL EXAMINATIONS. 



Final Examination. — (Goncludtd.) 



SPECIAL SUB.)ECTS. 



Sugar Industry. 



GENERAL. (1) Taking an area of fifty acres of sugar cane 

 land, give an account of the expenses of preparing the land 

 and establishing a crop of plant canes. (2) Give an account 

 of the use of artificial manures for .sugar-cane, under conditions 

 with which you are familiar, with special reference to the 

 best times for their application. (.3) AVrite an account of your 

 experience of root disease of the sugarcane (Marasnnus sp.), 

 and discuss the measures that have been suggested for its 

 control. 



MUSCOVADO METHOD. (1) It has been suggested that, in 

 making muscovado sugar, it may be advantageous to effect 

 all the evaporation in steam-heated pans. Discuss this 

 question, stating the advantages or disadvantages of the 

 method. (2) Descril)e carefully processes for separating the 

 molasses from muscovado sugar, and a method of storing the 

 former; more than one method of separation should be de- 

 scribed, and the merits compared. What precautions are 

 necessary to obtain molasses of good (|uality?!(3)What points 

 are essential to good work in the mill of a muscovado factory, 

 and how can you ascertain whether the mill is doing good or 

 bad work? Is it desirable to employ multipk mills, such as 

 those furnished with five or more rollers, in muscovado fac- 

 tories? Give reasons for your answer. 



VACUUM PAN METHOD. (1) Discuss the advantages pre- 

 sented by mills pos.sessing eleven and fourteen rollers, over 

 those having five and eight. How can you best ascertain if 

 the mills are doing good work? (2) Describe a suitable series 

 of proces.ses for producing 96° grey crystala and exhausted 

 molasses, commencing your description at the point where the 

 syrup leaves the triple effect. (3) Describe suitable methods 

 for effecting the clarification of cane juice when making 96° 

 grey crystals, stating what is essential to good work. What 

 ill eflfects may imperfect clarification exert in the sulisequent 

 stages of manufacture! What modification in the method of 

 clarification would you suggest in the event of having to deal 

 with ' gummy' juice I ,^ 



Cacao. 



(1) Give a description of a method of cidtivating cacao, 

 indicating the times of the year at which th§' various opera- 

 tions have to be carried out. (2) Write an account of the 

 principal fungus diseases of cacao, giving the measures for 

 control in each ease. (3) Supply details 6'Pthe quantities 

 and prices of the machinery and implements required for the 

 fermentation, curing and preparation of cidao for market, 

 on an estate bearing 25 acres of the crop. (Details concern- 

 ing the necessary buildings are not required.) 



T.imej. 



(1) How is citrate of lime manufactured!' What are the 

 advantages of the exportation of lime jutce produce in this 

 form? State how it is packed for .shipment, and what pre- 

 cautions are necessar}- during its carriage. (2) Write 

 a description of the cultural operations that are carried pn 

 during a year, on a lime estate, stating the object of each. 

 (3) Give details of the apparatus and machinery required for 

 crushing, and for the concentration of the juice from, the 

 fruit usually available from 75 acres of lime trees, under 

 circumstances with which you are familiar. 



Cotton. 



(1) Give an account of the arrangements that you would 

 make on an estate for the picking of the cotton crop and the 

 preparation of the seed-cotton for ginning. (2) Describe the 

 methods that may be employed for controlling the black scale 

 of cotton. (3) Supply details of your acquaintance with the 

 cultivation of land for cotton, and of its manurial treatment. 



Provision Crops. 



(1)1 )escribe methods that may be used for the improve- 

 ment of corn (maize) both by selection and hybridization. 

 (2) Give a careful description of the life-history and measures 

 for control of any insect pest of provision crops, with which 

 you are familiar. (3) What methods of cultivation are 

 employed in the case of the principal provision crops in your 

 district? Discuss the use of these crops in connexion with 

 systems of rotation, under circumstances of which you have 

 had experience. 



Para Rubber Seed Oil. — The subject of the indus- 

 trial application of the seeds of the Para rubber tree (Hurta 

 //1-asiliensis) was dealt with in a previous number of this 

 Bulletin (1911, 9, 35), when attention was again drawn to 

 the fact that the seeds yield a liquid drying oil very similar 

 in properties to linseed oil (see also this Bulletin, 1903, 1, 

 156; 1904, 2, 22). An investigation of the constituents of 

 the oil has since been made by Messrs. Pickles and Hayworth 

 in the laborarories of the Imperial Institute, and the results 

 have been communicated to the Society of Public Analysts 

 (see Analyst, 1911, 36, 491). The oil used in this investiga- 

 tion was extracted in this country from the kernels of unde- 

 corticated seeds. The kernels yielded 4SS per cent, of oil, 

 which was pale-yellow in colour, liquid at ordinary tempera- 

 tures, and dried to a hard varnish in about twelve days on 

 exposure to air. On examination the oil w'as found to have 

 the following constants ; — 



Specific gravity at 15 °/15° C. 09239 



Acid value 29 '9 



Saponification value 185' 6 



Iodine value, per cent. 1333 

 Titer test 33 ° C. 



Hehner value, per cent. 96 4 

 Reichert-Meissl value 05 



The composition of the mixed fatty acids was found to 

 be as follows: saturated (solid) acids ^i per cent., consisting 

 of stearic acid (m.p. 69 C.) and an acid or mixture of acids 

 (m.p. 56'5° (,'.); unsaturated (liquid) acids 86 per cent., con- 

 sisting of oleic acid 32'6 per cent., linoleic acid 50'9 per cent, 

 and linolenic acid 25 per cent. (Btdletin of the Imperial 

 Institute, Vol. IX, p. 286.) 



