119 



to have contained 124*29 lbs. chlorine and 4-08 lbs. nitrogen per 

 acre, and that for 1892, 109*7 lbs. chlorine and 2*27 nitrogen per acre. 

 Such examinations are extremely interesting, and allowing for known 

 sources of error, must be of the greatest use to the cultivator of the 

 soil in country where climate plays such an important part in sup- 

 plying material for plant growth as it does in Trinidad. 



168.-THB MANUFACTURE OF CASTOR OIL, 



\_Extract from Pharmaceutical Journal, May, 1895.^ 



" The system hitherto in use at the centres of this industry 

 involves, first of all. the separation of the husks from the kernels, 

 which are then heated and moulded into cakes and placed in horsehair 

 bags or cloths and submitted to pressure, which is almost invariably 

 obtained by manual power in India. In Marseilles and other centres 

 of Europe where castor oil is manufactured, hydraulic pressure is 

 usually applied. In the case of East Indian oil, the total oil taken 

 from the seed is usually extracted at one operation ; but where 

 hydraulic pressure is employed it is found more economical to press 

 twice, and by this means extract a larger percentage of oil from the 

 seed. The Calcutta marc from castor crushing contains about 20 per 

 cent, of oil, whei'eas by the other systems it is considerably less than 

 half that amount. This mode of manufacture has many objectionable 

 features, being complicated and unnecessarily expensive, and most 

 injurious as regards the quality of both the oil and the cake so 

 produced. 



The system adopted in the present case has been introduced by 

 the British Castor Oil Company's Engineer, who has invented and 

 patented most of the apparatus employed. Guzzerat seed is exclu- 

 sively employed for the preparation, both of the medicinal and the 

 lubricating oils, so as to ensure a uniform product, as it is the only 

 variety which can readily be obtained free from admixture. 



The first floor of the building is used as a granary, and here the 

 seed is carefully sifted, so as to get rid of any extraneous matter. It 

 it is then shot into a movable hopper, which is drawn along the top of 

 the large horizontal hydraulic press situated on the ground floor. 

 When the press boxes are open the seed is discharged through the 

 aperture at the bottom of the hopper, and fills the boxes. A pressure 

 of 480 tons is then applied, and the oil is expressed, falling upon a 

 movable plate and into drains provided for its reception along each 



