121 



After the seed has undergone the first pressure, whereby half 

 of the available 44 per cent, of oil has been collected for medi- 

 cinal purposes, the residual cake is again submitted to the same 

 treatment. This takes out an additional 16 per cent, of oil finally 

 leaving about 6 per cent, in the marc. The second product 

 goes through a similar process to the first, except that it is only 

 filtered once, and that three instead of four cloths are employed 

 for the purpose. The finished product, which is sold exclusively for 

 lubricating purposes, as a matter of fact closely resembles the medi- 

 cinal oil, but has a slightly nauseous taste. The marc left after the 

 second extraction is at present entirely used for horticultural pur- 

 poses under the name of " Foodite." Analysis shows it to contain 

 7'28 per cent, of nitrogen, equivalent to 8'84 per cent, of ammonia. 



The present director Avas engaged in the manufacture of castor oil 

 in India for some twelve years, and the process now employed by him 

 embodies all the best points of his experience in the diiFerent oil- 

 producing centres. In Calcutta alone there are more than 300 mills 

 engaged in crushing castor oil seed, but the system there employed, 

 as already explained, involves the husking of the seed prior to sub- 

 mitting it to pressure. However, a mill is being erected there 

 in which the present process has been adopted. The advantages 

 claimed for crushing the whole seed are that the process is much 

 more expeditious, less costly, and that there is no danger of internal 

 pressure, such as is liable to occur Avhen the kernels only are sub- 

 mitted to pressure. 



Obviously this system of extraction is applicable to many other 

 seeds besides castor. In fact it has been tried with extremely satis- 

 factory results with linseed. In this instance, after about 27 per 

 cent, of oil had been extracted by cold pressure, the seed was but 

 little altered in appearance, and would doubtless be very useful in 

 that state for cattle food, the expense of making it into cake being 

 unnecessary. Besides this, several purposes for which it could with 

 advantage be used pharmaceutically, suggest themselves. The most 

 important economic use of the seed, however, is as a source of oil." 



169. -BOTANICAL NOTES. 



No. 1. — Polypodiuvi trinidadense, n. sp., Jenman. 



Under this name there has recently been described a fern which 

 was collected by the writer at Maracas Falls some five years since. 



